Move all toolchain installation in TOOLCHAIN directory. #2163

Job	Run time
Macos (native_dyn)	13m 21s
Macos (native_static)	11m 49s
Linux (native_static, focal)	14m 46s
Macos (native_mixed)	11m 40s
Linux (native_dyn, focal)	7m 22s
Flatpak	17m 54s
Linux (native_mixed, focal)	11m 26s
Macos (iOS_arm64)	12m 56s
Linux (wasm, focal)	4m 12s
Macos (iOS_x86_64)	16m 41s
Linux (armv6_static, focal)	39s
Linux (armv6_dyn, focal)	37s
Macos (iOS_Mac_ABI)	13m 51s
Linux (armv6_mixed, focal)	34s
Macos (macOS_arm64_static)	14m 14s
Linux (armv8_static, focal)	35s
Macos (macOS_arm64_mixed)	15m 14s
Linux (armv8_dyn, focal)	53s
Macos (macOS_x86_64)	17m 19s
Linux (armv8_mixed, focal)	42s
Linux (aarch64_static, focal)	45s
Linux (aarch64_dyn, focal)	39s
Linux (aarch64_mixed, focal)	37s
Linux (aarch64_musl_static, focal)	44s
Linux (aarch64_musl_dyn, focal)	33s
Linux (aarch64_musl_mixed, focal)	37s
Linux (x86-64_musl_static, focal)	34s
Linux (x86-64_musl_dyn, focal)	44s
Linux (x86-64_musl_mixed, focal)	46s
Linux (i586_static, focal)	12m 3s
Linux (i586_dyn, focal)	11m 49s
Linux (android_arm, focal)	37s
Linux (android_arm64, focal)	54s
Linux (android_x86, focal)	41s
Linux (android_x86_64, focal)	42s
Linux (native_mixed, bionic)	9m 47s
Linux (aarch64_mixed, bionic)	23s
Linux (win32_static, f35)	10m 44s
Linux (win32_dyn, f35)	11m 24s
	4h 11m 48s

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