Auto merge of #132584 - Zalathar:includes, r=cuviper

Trim and tidy includes in `rustc_llvm`

These includes tend to accumulate over time, and are usually only removed when something breaks in a new LLVM version, so it's nice to clean them up manually once in a while.

General strategy used for this PR:
- Remove all includes from `LLVMWrapper.h` that aren't needed by the header itself, transplanting them to individual source files as necessary.
- For each source file, temporarily remove each include if doing so doesn't cause a compile error.
- If a “required” include looks like it shouldn't be needed, try replacing it with its sub-includes, then trim that list.
- After doing all of the above, go back and re-add any removed include if the file does actually use things defined in that header, even if the header happens to also be included by something else.

compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp

@@ -1,5 +1,9 @@
 #include "LLVMWrapper.h"
+
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/Module.h"
 #include "llvm/ProfileData/Coverage/CoverageMapping.h"
 #include "llvm/ProfileData/Coverage/CoverageMappingWriter.h"
 #include "llvm/ProfileData/InstrProf.h"