[clang-tools-extra] [lld] [llvm] tools: Remove untested PluginLoader includes (PR #117644)

[via cfe-commits]

github-actions[bot] wrote:

<!--LLVM CODE LINT COMMENT: clang-tidy-->


:warning: C/C++ code linter, clang-tidy found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

```bash

git diff -U0 origin/main...HEAD -- clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp |
python3 clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py   -path build -p1 -quiet
```

</details>

<details>
<summary>
View the output from clang-tidy here.
</summary>

```
clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp:26:1: warning: included header PluginLoader.h is not used directly [misc-include-cleaner]
   26 | #include "llvm/Support/PluginLoader.h"
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   27 | #include "llvm/Support/Process.h"
```

</details>


https://github.com/llvm/llvm-project/pull/117644