[llvm] [BOLT][AArch64] Skip gadget pacret test on RHEL8 (PR #145527)

[Paschalis Mpeis via llvm-commits]

paschalis-mpeis wrote:

Hey @atrosinenko and @kbeyls,

This tests fails on RHEL8. I am disabling it on that platform and letting you know in case it needs your attention.

I don't have a full RHEL8 environment, but I tested the os+version check I introduced in isolation.

Some (truncated) error logs I received:
```
**00:15:27**  ********************
**00:15:27**  Testing: 
**00:15:27**  FAIL: BOLT :: binary-analysis/AArch64/gs-pacret-autiasp.s (551 of 92523)
**00:15:27**  ******************** TEST 'BOLT :: binary-analysis/AArch64/gs-pacret-autiasp.s' FAILED ********************
**00:15:27**  Exit Code: 1
**00:15:27**  
**00:15:27**  Command Output (stderr):
**00:15:27**  + /workspace/build/stage/shared_lib_build/bin/llvm-bolt-binary-analysis --scanners=pacret /workspace/build/stage/shared_lib_build/tools/bolt/test/binary-analysis/AArch64/Output/gs-pacret-autiasp.s.tmp.exe
**00:15:27**  /workspace/src/bolt/test/binary-analysis/AArch64/gs-pacret-autiasp.s:21:16: error: CHECK-NEXT: is not on the line after the previous match
**00:15:27**  // CHECK-NEXT: {{[0-9a-f]+}}: add x0, x0, #0x3
**00:15:27**                 ^
**00:15:27**  <stdin>:17:2: note: 'next' match was here
**00:15:27**   00010308: add x0, x0, #0x3
**00:15:27**   ^
**00:15:27**  <stdin>:12:44: note: previous match ended here
**00:15:27**   This happens in the following basic block:
**00:15:27**                                             ^
**00:15:27**  <stdin>:13:1: note: non-matching line after previous match is here
**00:15:27**   000102f8: paciasp
**00:15:27**  ^
**00:15:27**  /workspace/src/bolt/test/binary-analysis/AArch64/gs-pacret-autiasp.s:43:16: error: CHECK-NEXT: is not on the line after the previous match
**00:15:27**  // CHECK-NEXT: {{[0-9a-f]+}}: add x0, x0, #0x3
**00:15:27**                 ^
**00:15:27**  <stdin>:30:2: note: 'next' match was here
**00:15:27**   00010324: add x0, x0, #0x3
**00:15:27**   ^
**00:15:27**  <stdin>:25:44: note: previous match ended here
**00:15:27**   This happens in the following basic block:
**00:15:27**                                             ^
**00:15:27**  <stdin>:26:1: note: non-matching line after previous match is here
**00:15:27**   00010314: paciasp
**00:15:27**  ^
... (truncated)
```

(cc: @pawosm-arm)

https://github.com/llvm/llvm-project/pull/145527