Test

use `IS_SLASH` in various places instead of string comparing #1907

Job	Run time
Generate Matrix	12s
Suite / ALPINE_X64_ASAN_DEBUG_ZTS	29m 58s
Suite / LINUX_X32_DEBUG_ZTS	11m 1s
Suite / LINUX_X64_RELEASE_NTS	22m 6s
Suite / LINUX_X64_ASAN_DEBUG_ZTS	42m 55s
Suite / BENCHMARKING	12m 38s
Suite / FREEBSD_NTS	12m 16s
Suite / WINDOWS_X64_ZTS	33m 31s
Suite / MACOS_ARM64_DEBUG_NTS	15m 18s
Suite / LINUX_PPC64_ASAN_DEBUG_ZTS	0s
Suite / COMMUNITY_${{ matrix.type }}	0s
Suite / SOLARIS	0s
Suite / COVERAGE	0s
Suite / PECL	0s
Suite / MSAN	0s
Suite / LIBMYSQLCLIENT	0s
Suite / OPCACHE_VARIATION	-1s
	2h 59m 54s

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