Merge .sdata, .srodata and .sbss #4092

Job	Run time
build-gcc	17m 52s
build-macos (-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On)	7m 29s
build-distros (alpine)	14m 44s
build-macos (-DMOLD_USE_ASAN=On)	17m 26s
build-clang (-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On)	11m 18s
build-distros (archlinux)	16m 44s
build-msys	10m 34s
build-clang (-DMOLD_USE_TSAN=On)	18m 4s
build-distros (fedora)	11m 33s
build-distros (gentoo/stage3)	17m 29s
build-windows	28m 28s
build-distros (opensuse/tumbleweed)	11m 35s
	3h 3m 16s

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