Add O_RSYNC + fallocate on solarish, and fadvise on illumos #4363

Job	Run time
Check nightly-only targets (nightly)	24s
Check selected Tier 3 platforms (nightly)	4m 44s
Check --no-default-features (nightly)	54s
Check (stable)	6m 7s
Check (nightly)	6m 34s
Rustfmt	13s
Check (1.63)	10m 2s
Test rustix_use_experimental_asm (powerpc64le-linux)	1m 26s
Test (ubuntu)	43s
Test rustix_use_experimental_asm (s390x-linux)	1m 0s
Test use-libc (ubuntu)	49s
Test (ubuntu-20.04)	42s
Test (i686-linux)	1m 6s
Test (aarch64-linux)	1m 12s
Test use-libc (i686-linux)	58s
Test (powerpc64le-linux)	1m 14s
Test use-libc (aarch64-linux)	1m 7s
Test use-libc (powerpc64le-linux)	1m 4s
Test (riscv64-linux)	1m 6s
Test use-libc (riscv64-linux)	1m 6s
Test (s390x-linux)	1m 3s
Test use-libc (s390x-linux)	1m 5s
Test (arm-linux)	57s
Test use-libc (arm-linux)	1m 0s
Test (ubuntu-stable)	44s
Test (i686-linux-stable)	1m 1s
Test (aarch64-linux-stable)	1m 4s
Test (riscv64-linux-stable)	56s
Test (s390x-linux-stable)	1m 22s
Test (powerpc64le-linux-stable)	1m 3s
Test (arm-linux-stable)	1m 8s
Test (ubuntu-1.63)	2m 0s
Test (i686-linux-1.63)	2m 15s
Test (aarch64-linux-1.63)	2m 38s
Test (riscv64-linux-1.63)	2m 12s
Test (s390x-linux-1.63)	2m 29s
Test (powerpc64le-linux-1.63)	2m 32s
Test (arm-linux-1.63)	2m 22s
Test (macos-latest)	39s
Test (macos-12)	1m 5s
Test (windows)	47s
Test (windows-2019)	57s
Test (musl)	47s
	1h 14m 37s

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