[clang] [lld] [llvm] [Clang][WebAssembly] Add wasm_global declaration attribute (PR #221909)

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github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 143898 tests passed
* 3515 tests skipped
* 1 test failed

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

### Clang
<details>
<summary>Clang.CodeGen/WebAssembly/wasm-global-attribute.cpp</summary>

```
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\24\include -nostdsysteminc -triple wasm32-unknown-unknown-wasm -emit-llvm -o - C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\24\include' -nostdsysteminc -triple wasm32-unknown-unknown-wasm -emit-llvm -o - 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp:7:5: error: redefinition of 'redeclared_g' with a different type: 'int' vs '__attribute__((address_space(1))) int'
# |     7 | int redeclared_g = 0;
# |       |     ^
# | C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp:6:12: note: previous declaration is here
# |     6 | extern int redeclared_g [[clang::wasm_global]];
# |       |            ^
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp'
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\WebAssembly\wasm-global-attribute.cpp
# `-----------------------------
# error: command failed with exit status: 2

--

```
</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/221909