[LoongArch] Support TLSDESC #4108

Job	Run time
build-gcc	28m 37s
build-distros (alpine)	14m 46s
build-clang (-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On)	11m 39s
build-distros (archlinux)	16m 38s
build-clang (-DMOLD_USE_TSAN=On)	17m 33s
build-msys	10m 42s
build-distros (fedora)	11m 34s
build-macos (-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On)	6m 50s
build-distros (gentoo/stage3)	17m 49s
build-macos (-DMOLD_USE_ASAN=On)	23m 17s
build-distros (opensuse/tumbleweed)	11m 39s
build-windows	29m 25s
	3h 20m 29s

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