[llvm] [AArch64] Define high bits of FPR and GPR registers (take 2) (PR #114827)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `premerge-monolithic-linux` running on `premerge-linux-1` while building `llvm` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/14632

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

```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'BOLT-Unit :: Core/./CoreTests/11/23' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/build/buildbot/premerge-monolithic-linux/build/tools/bolt/unittests/Core/./CoreTests-BOLT-Unit-1195098-11-23.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=23 GTEST_SHARD_INDEX=11 /build/buildbot/premerge-monolithic-linux/build/tools/bolt/unittests/Core/./CoreTests
--

Script:
--
/build/buildbot/premerge-monolithic-linux/build/tools/bolt/unittests/Core/./CoreTests --gtest_filter=AArch64/MCPlusBuilderTester.AliasX0/0
--
/build/buildbot/premerge-monolithic-linux/llvm-project/bolt/unittests/Core/MCPlusBuilder.cpp:76: Failure
Expected equality of these values:
  BV.count()
    Which is: 6
  Count
    Which is: 5


/build/buildbot/premerge-monolithic-linux/llvm-project/bolt/unittests/Core/MCPlusBuilder.cpp:76
Expected equality of these values:
  BV.count()
    Which is: 6
  Count
    Which is: 5



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


```

</details>

https://github.com/llvm/llvm-project/pull/114827