Remove 'CLANG_BUILD' env variable usage (#400) #2473

Job	Run time
python-lint	4s
clang-format	12s
windows-msvc-build	2m 38s
ubuntu-clang-build (ubuntu-24.04)	1m 17s
ubuntu-clang-build (ubuntu-24.04-arm)	2m 31s
ubuntu-gcc-build (ubuntu-24.04-arm)	3m 17s
windows-clang-build	3m 40s
ubuntu-gcc-build (ubuntu-24.04)	56s
macos-clang-build	1m 43s
windows-msvc-test	2m 17s
windows-clang-test	1m 21s
macos-clang-test	2m 43s
ubuntu-clang-sanitizer-build (ubuntu-24.04)	1m 11s
ubuntu-clang-test (ubuntu-24.04)	4m 34s
ubuntu-clang-test (ubuntu-24.04-arm)	4m 53s
ubuntu-gcc-test (ubuntu-24.04-arm)	4m 48s
ubuntu-gcc-test (ubuntu-24.04)	4m 12s
windows-msvc-test-extended	1m 16s
windows-clang-test-extended	1m 15s
macos-clang-test-extended	2m 0s
ubuntu-clang-test-extended (ubuntu-24.04-arm)	4m 7s
ubuntu-clang-test-extended (ubuntu-24.04)	2m 45s
ubuntu-clang-sanitizer-test (ubuntu-24.04)	1m 48s
ubuntu-gcc-test-extended (ubuntu-24.04)	4m 5s
ubuntu-gcc-test-extended (ubuntu-24.04-arm)	3m 42s
ubuntu-clang-sanitizer-test-extended (ubuntu-24.04)	1m 42s
ubuntu-gcc-build-codecov	4m 37s
ubuntu-gcc-build-perf-stats	1m 1s
	1h 10m 35s

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