[clang-format] Handle attributes before case label. Relanded.

Fixes https://github.com/llvm/llvm-project/issues/53110.

Reviewed By: MyDeveloperDay, HazardyKnusperkeks, owenpan

Differential Revision: https://reviews.llvm.org/D121450

Relanding as the original patch provoked an infinite loop in JavaScript/TypeScript.
A reproducer test case was added and the issue fixed.