[llvm] [compiler-rt] follow-up to 166837, rename COMPILER_RT_FORCE_TEST_BUILTINS_DIR to COMPILER_RT_TEST_BUILTINS_DIR (PR #171741)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-rhel` running on `ppc64le-clang-rhel-test` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/145/builds/11398

<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 'Builtins-powerpc64le-linux :: ppc/fixtfti_test.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/./bin/clang   -gline-tables-only  -m64 -fno-function-sections  -fno-builtin -I /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/compiler-rt/lib/builtins -nodefaultlibs /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/compiler-rt/test/builtins/Unit/ppc/fixtfti_test.c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/./lib/../lib/clang/22/lib/powerpc64le-unknown-linux-gnu/libclang_rt.builtins.a -lc -lm -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/POWERPC64LELinuxConfig/ppc/Output/fixtfti_test.c.tmp &&  /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/POWERPC64LELinuxConfig/ppc/Output/fixtfti_test.c.tmp
# executed command: /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/./bin/clang -gline-tables-only -m64 -fno-function-sections -fno-builtin -I /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/compiler-rt/lib/builtins -nodefaultlibs /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/compiler-rt/test/builtins/Unit/ppc/fixtfti_test.c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/./lib/../lib/clang/22/lib/powerpc64le-unknown-linux-gnu/libclang_rt.builtins.a -lc -lm -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/POWERPC64LELinuxConfig/ppc/Output/fixtfti_test.c.tmp
# executed command: /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins/compiler-rt/test/builtins/Unit/POWERPC64LELinuxConfig/ppc/Output/fixtfti_test.c.tmp
# .---command stdout------------
# | Error for __fixtfti at input 0x1.be1c2ac37c3846ed5efd1ddabep+0 = ( 0x1.be1c2ac37c385p+0 , -0x1.2254205c44a84p-53 ):
# | 	Expected __int128_t: 0x0000000000000000 0x0000000000000001
# | 	Computed __int128_t: 0x0000000000000912 0xa102e22542000001
# | 
# `-----------------------------
# error: command failed with exit status: 1

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/171741