[clang] [Clang] Improve __block attribute coverage for ivars and static variables (PR #198167)

[via cfe-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 88023 tests passed
* 1572 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.SemaObjC/block-on-method-param.m</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -triple x86_64-apple-darwin10 -fsyntax-only -verify -fblocks -Wno-objc-root-class /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -triple x86_64-apple-darwin10 -fsyntax-only -verify -fblocks -Wno-objc-root-class /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m
# .---command stderr------------
# | error: 'expected-error' diagnostics expected but not seen: 
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m Line 5: __block attribute not allowed, only allowed on local variables
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m Line 9: __block attribute not allowed, only allowed on local variables
# | error: 'expected-error' diagnostics seen but not expected: 
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m Line 5: '__block' is not allowed on a nonlocal variable
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaObjC/block-on-method-param.m Line 9: '__block' is not allowed on a nonlocal variable
# | 4 errors generated.
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/198167