[llvm] [MachinePipeliner] Fix constraints aren't considered in certain cases (PR #95356)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64be-linux-test-suite` running on `ppc64be-clang-test-suite` while building `llvm` at step 7 "test-build-unified-tree-check-runtimes".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/176/builds/576

Here is the relevant piece of the build log for the reference:
```
Step 7 (test-build-unified-tree-check-runtimes) failure: test (failure)
******************** TEST 'SanitizerCommon-lsan-powerpc64-Linux :: Linux/soft_rss_limit_mb_test.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/./bin/clang  --driver-mode=g++ -gline-tables-only -fsanitize=leak  -m64 -funwind-tables  -I/home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test -ldl -O2 /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp -o /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/lsan-powerpc64-Linux/Linux/Output/soft_rss_limit_mb_test.cpp.tmp
+ /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/./bin/clang --driver-mode=g++ -gline-tables-only -fsanitize=leak -m64 -funwind-tables -I/home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test -ldl -O2 /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp -o /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/lsan-powerpc64-Linux/Linux/Output/soft_rss_limit_mb_test.cpp.tmp
RUN: at line 5: env LSAN_OPTIONS=soft_rss_limit_mb=220:quarantine_size=1:allocator_may_return_null=1      /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/lsan-powerpc64-Linux/Linux/Output/soft_rss_limit_mb_test.cpp.tmp 2>&1 | FileCheck /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp -check-prefix=CHECK_MAY_RETURN_1
+ env LSAN_OPTIONS=soft_rss_limit_mb=220:quarantine_size=1:allocator_may_return_null=1 /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/lsan-powerpc64-Linux/Linux/Output/soft_rss_limit_mb_test.cpp.tmp
+ FileCheck /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp -check-prefix=CHECK_MAY_RETURN_1
/home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp:68:24: error: CHECK_MAY_RETURN_1: expected string not found in input
// CHECK_MAY_RETURN_1: allocating 512 times
                       ^
<stdin>:52:44: note: scanning from here
Some of the malloc calls returned non-null: 256
                                           ^
<stdin>:53:13: note: possible intended match here
==131393==LeakSanitizer: soft rss limit unexhausted (220Mb vs 95Mb)
            ^

Input file: <stdin>
Check file: /home/buildbots/llvm-external-buildbots/workers/ppc64be-clang-test-suite/clang-ppc64be-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/soft_rss_limit_mb_test.cpp

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            .
            .
            .
           47:  [256] 
           48:  [320] 
           49:  [384] 
           50:  [448] 
           51: Some of the malloc calls returned null: 256 
           52: Some of the malloc calls returned non-null: 256 
check:68'0                                                X~~~~ error: no match found
           53: ==131393==LeakSanitizer: soft rss limit unexhausted (220Mb vs 95Mb) 
check:68'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:68'1                 ?                                                        possible intended match
>>>>>>

--

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


```

https://github.com/llvm/llvm-project/pull/95356