Fix some IWYU issues. #4075

Job	Run time
ClangTidy	6m 40s
KytheXrefs	0s
KytheVerification	11m 5s
x86_64 test	3m 46s
MacOsBuild	15m 10s
arm64 test	12m 24s
MacOsBuildDevTools	6m 52s
Generate Build matrix	4s
x86_64 test-nortti	3m 35s
x86_64 test-c++20	3m 38s
x86_64 test-c++23	3m 32s
PrepareVSPlugin	1m 58s
VerifyFormatting	1m 41s
x86_64 smoke-test	10m 19s
WindowsBuild	17m 31s
arm64 smoke-test	11m 18s
x86_64 smoke-test-analyzer	14m 44s
arm64 smoke-test-analyzer	15m 57s
x86_64 asan	10m 20s
x86_64 asan-clang	7m 57s
x86_64 compile	2m 55s
arm64 compile	3m 41s
x86_64 compile-clang	2m 32s
arm64 compile-clang	3m 39s
x86_64 compile-static	2m 48s
arm64 compile-static	3m 40s
x86_64 compile-static-clang	6m 55s
arm64 compile-static-clang	7m 0s
x86_64 coverage	17m 43s
x86_64 clean	7m 1s
arm64 clean	6m 30s
Build ·${{ matrix.arch }}:${{ matrix.os }}:${{ matrix.ver }}${{ (((matrix.link == 'static') && ':static') \|\| '') }}	0s
Build and deploy GitHub pages	12s
📦 Release	0s
	3h 43m 7s

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