Re-enable several cross-compilation targets in CI. #4177

Job	Run time
Rustfmt	3s
Check nightly-only targets (nightly)	23s
Check (stable)	3m 28s
Check --no-default-features (nightly)	53s
Check selected Tier 3 platforms (nightly)	4m 24s
Check (nightly)	3m 27s
Check (1.63)	3m 23s
Test rustix_use_experimental_asm (powerpc64le-linux)	1m 34s
Test (ubuntu)	42s
Test use-libc (ubuntu)	36s
Test (ubuntu-20.04)	42s
Test use-libc (i686-linux)	52s
Test (i686-linux)	57s
Test use-libc (aarch64-linux)	2m 7s
Test (aarch64-linux)	1m 21s
Test use-libc (powerpc64le-linux)	1m 5s
Test (powerpc64le-linux)	1m 11s
Test use-libc (riscv64-linux)	1m 2s
Test (riscv64-linux)	1m 7s
Test use-libc (arm-linux)	1m 20s
Test (s390x-linux)	1m 11s
Test (arm-linux)	1m 0s
Test (ubuntu-stable)	37s
Test (i686-linux-stable)	59s
Test (aarch64-linux-stable)	59s
Test (riscv64-linux-stable)	1m 2s
Test (s390x-linux-stable)	57s
Test (powerpc64le-linux-stable)	1m 29s
Test (arm-linux-stable)	1m 0s
Test (ubuntu-1.63)	2m 42s
Test (i686-linux-1.63)	2m 52s
Test (aarch64-linux-1.63)	2m 51s
Test (riscv64-linux-1.63)	2m 51s
Test (s390x-linux-1.63)	2m 50s
Test (powerpc64le-linux-1.63)	2m 58s
Test (arm-linux-1.63)	2m 59s
Test (macos-latest)	7m 43s
Test (macos-12)	7m 44s
Test (windows)	50s
Test (windows-2019)	1m 15s
Test (musl)	41s
	1h 18m 7s

Provide feedback