Remove 'CLANG_BUILD' env variable usage (#400) #2479

Job	Run time
clang-format	9s
python-lint	5s
ubuntu-gcc-build (ubuntu-24.04)	49s
ubuntu-gcc-build (ubuntu-24.04-arm)	3m 38s
ubuntu-clang-build (ubuntu-24.04)	1m 10s
ubuntu-clang-build (ubuntu-24.04-arm)	2m 28s
windows-msvc-build	2m 19s
windows-clang-build	3m 21s
macos-clang-build	1m 40s
macos-clang-test	2m 51s
windows-clang-test	1m 22s
windows-msvc-test	2m 13s
ubuntu-clang-sanitizer-build (ubuntu-24.04)	1m 34s
ubuntu-clang-test (ubuntu-24.04)	4m 29s
ubuntu-clang-test (ubuntu-24.04-arm)	5m 6s
macos-clang-test-extended	1m 54s
ubuntu-gcc-test (ubuntu-24.04-arm)	5m 27s
ubuntu-gcc-test (ubuntu-24.04)	4m 16s
windows-clang-test-extended	1m 24s
windows-msvc-test-extended	1m 23s
ubuntu-clang-sanitizer-test (ubuntu-24.04)	1m 54s
ubuntu-clang-test-extended (ubuntu-24.04-arm)	3m 21s
ubuntu-clang-test-extended (ubuntu-24.04)	3m 28s
ubuntu-gcc-test-extended (ubuntu-24.04-arm)	3m 23s
ubuntu-gcc-test-extended (ubuntu-24.04)	2m 21s
ubuntu-clang-sanitizer-test-extended (ubuntu-24.04)	1m 48s
ubuntu-gcc-build-codecov	3m 22s
ubuntu-gcc-build-perf-stats	1m 2s
	1h 8m 17s

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