[llvm] [TableGen] Avoid assignmentInAssert warning (PR #139715)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-darwin` running on `doug-worker-3` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/23/builds/10255

<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 'LLVM :: TableGen/GlobalISelCombinerEmitter/match-table-cxx.td' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen -I /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner      -combiners=MyCombiner /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td |  /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td # RUN: at line 1
+ /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen -I /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner -combiners=MyCombiner /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td
+ /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td
Assertion failed: (ExpectedID == ID && "combine rules are not ordered!"), function emitTestSimplePredicate, file GlobalISelCombinerEmitter.cpp, line 2615.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen -I /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner -combiners=MyCombiner /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td
 #0 0x00000001068a39a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x10032d9a8)
 #1 0x00000001068a19a8 llvm::sys::RunSignalHandlers() (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x10032b9a8)
 #2 0x00000001068a4080 SignalHandler(int, __siginfo*, void*) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x10032e080)
 #3 0x00007ff80a867fdd (/usr/lib/system/libsystem_platform.dylib+0x7ff80046afdd)
 #4 0x00007ff80a65743d (/usr/lib/system/libsystem_malloc.dylib+0x7ff80025a43d)
 #5 0x00007ff80a75ea79 (/usr/lib/system/libsystem_c.dylib+0x7ff800361a79)
 #6 0x00007ff80a75dd68 (/usr/lib/system/libsystem_c.dylib+0x7ff800360d68)
 #7 0x000000010693a863 (anonymous namespace)::GICombinerEmitter::emitTestSimplePredicate(llvm::raw_ostream&) (.cold.1) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x1003c4863)
 #8 0x0000000106766ac7 (anonymous namespace)::GICombinerEmitter::emitTestSimplePredicate(llvm::raw_ostream&) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x1001f0ac7)
 #9 0x00000001065e1824 llvm::GlobalISelMatchTableExecutorEmitter::emitExecutorImpl(llvm::raw_ostream&, llvm::gi::MatchTable const&, llvm::ArrayRef<llvm::gi::LLTCodeGen>, llvm::ArrayRef<llvm::gi::RuleMatcher>, llvm::ArrayRef<llvm::Record const*>, llvm::ArrayRef<llvm::StringRef>, llvm::StringRef) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x10006b824)
#10 0x00000001067658fd (anonymous namespace)::GICombinerEmitter::run(llvm::raw_ostream&) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x1001ef8fd)
#11 0x000000010676140d EmitGICombiner(llvm::RecordKeeper const&, llvm::raw_ostream&) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x1001eb40d)
#12 0x00000001068cf15f llvm::TableGen::Emitter::ApplyCallback(llvm::RecordKeeper const&, llvm::raw_ostream&) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x10035915f)
#13 0x00000001068aa7ba llvm::TableGenMain(char const*, std::__1::function<bool (llvm::raw_ostream&, llvm::RecordKeeper const&)>) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x1003347ba)
#14 0x00000001065b6794 tblgen_main(int, char**) (/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/llvm-tblgen+0x100040794)
#15 0x00007ff80a4ad345 
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-cxx.td

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/139715