[llvm] MC: Refine ALIGN relocation conditions (PR #150816)

[Kito Cheng via llvm-commits]

kito-cheng wrote:

Share you my test scripts, it seems still some corner case isn't handled well.

The test script will show all step and why it fail :)

Setup
```shell
$ git clone git at github.com:kito-cheng/riscv-alignment-check.git
$ cd riscv-alignment-check
$ wget https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/2025.07.16/riscv64-glibc-ubuntu-22.04-gcc-nightly-2025.07.16-nightly.tar.xz
$ tar -xf riscv64-glibc-ubuntu-22.04-gcc-nightly-2025.07.16-nightly.tar.xz
```

How to run:
```shell
./test_runner.py --toolchain-base `pwd`/riscv/bin --clang --clang-path <path-to-clang> | tee log
```

Result for this PR:
```
==================================================
TEST SUMMARY
==================================================
norvc                     PASS
norvc-norelax             PASS
norelax                   PASS
relax-rvc                 PASS
relax1-norvc              FAIL
relax1-norvc-norelax      FAIL
relax1-norelax            PASS
relax1-relax-rvc          PASS
relax2-norvc              PASS
relax2-norvc-norelax      PASS
relax2-norelax            PASS
relax2-relax-rvc          PASS
relax3-norvc              FAIL
relax3-norvc-norelax      FAIL
relax3-norelax            PASS
relax3-relax-rvc          PASS
relax4-norvc              PASS
relax4-norvc-norelax      PASS
relax4-norelax            PASS
relax4-relax-rvc          PASS
relax5-norvc              PASS
relax5-norvc-norelax      PASS
relax5-norelax            PASS
relax5-relax-rvc          PASS
relax6-norvc              PASS
relax6-norvc-norelax      PASS
relax6-norelax            PASS
relax6-relax-rvc          PASS
relax7-norvc              FAIL
relax7-norvc-norelax      FAIL
relax7-norelax            FAIL
relax7-relax-rvc          FAIL
relax8-norvc              PASS
relax8-norvc-norelax      PASS
relax8-norelax            PASS
relax8-relax-rvc          PASS
relax9-norvc              PASS
relax9-norvc-norelax      PASS
relax9-norelax            PASS
relax9-relax-rvc          PASS
relax10-norvc             PASS
relax10-norvc-norelax     PASS
relax10-norelax           PASS
relax10-relax-rvc         PASS
relax11-norvc             PASS
relax11-norvc-norelax     PASS
relax11-norelax           PASS
relax11-relax-rvc         PASS
relax12-norvc             PASS
relax12-norvc-norelax     PASS
relax12-norelax           PASS
relax12-relax-rvc         PASS

Results: 44/52 tests passed
Some tests failed! ✗

```


https://github.com/llvm/llvm-project/pull/150816