[clang] [Frontend][PCH]-Add support for ignoring PCH options (-ignore-pch). (PR #142409)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-4` while building `clang` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/21187

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Modules/crash-vfs-include-pch.m' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
rm -rf /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp # RUN: at line 3
+ rm -rf /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp
mkdir -p /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/m /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out # RUN: at line 4
+ mkdir -p /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/m /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out
/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/clang -cc1 -internal-isystem /Users/buildbot/buildbot-root/aarch64-darwin/build/lib/clang/21/include -nostdsysteminc -x objective-c-header -emit-pch /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/pch-used.h      -o /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out/pch-used.h.pch -fmodules -fimplicit-module-maps      -fbuiltin-headers-in-system-modules -fmodules-cache-path=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/cache -O0      -isystem /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/System/usr/include # RUN: at line 6
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/clang -cc1 -internal-isystem /Users/buildbot/buildbot-root/aarch64-darwin/build/lib/clang/21/include -nostdsysteminc -x objective-c-header -emit-pch /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/pch-used.h -o /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out/pch-used.h.pch -fmodules -fimplicit-module-maps -fbuiltin-headers-in-system-modules -fmodules-cache-path=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/cache -O0 -isystem /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/System/usr/include
env FORCE_CLANG_DIAGNOSTICS_CRASH= TMPDIR=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp TEMP=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp TMP=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp  not /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/clang /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -E -include-pch /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out/pch-used.h.pch -fmodules -nostdlibinc      -fimplicit-module-maps -Xclang -fbuiltin-headers-in-system-modules      -fmodules-cache-path=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/cache -O0 -Xclang -fno-validate-pch      -isystem /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/System/usr/include -o /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/output.E 2>&1 | /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m # RUN: at line 11
+ env FORCE_CLANG_DIAGNOSTICS_CRASH= TMPDIR=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp TEMP=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp TMP=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp not /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/clang /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -E -include-pch /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/out/pch-used.h.pch -fmodules -nostdlibinc -fimplicit-module-maps -Xclang -fbuiltin-headers-in-system-modules -fmodules-cache-path=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/cache -O0 -Xclang -fno-validate-pch -isystem /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/Inputs/System/usr/include -o /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/output.E
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m
/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck --check-prefix=CHECKSH /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -input-file /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/crash-vfs-*.sh # RUN: at line 17
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck --check-prefix=CHECKSH /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -input-file /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/crash-vfs-include-pch-c7e35e.sh
/Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck --check-prefix=CHECKYAML /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -input-file    /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/crash-vfs-*.cache/vfs/vfs.yaml # RUN: at line 18
+ /Users/buildbot/buildbot-root/aarch64-darwin/build/bin/FileCheck --check-prefix=CHECKYAML /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/test/Modules/crash-vfs-include-pch.m -input-file '/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/crash-vfs-*.cache/vfs/vfs.yaml'
Could not open input file '/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/test/Modules/Output/crash-vfs-include-pch.m.tmp/crash-vfs-*.cache/vfs/vfs.yaml': No such file or directory

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/142409