Redo ghc-install.sh, fixes #913 #972

Job	Run time
Build ARM binary (self-hosted, Linux, ARM64, armv7-linux-ghcup, 9.2.2, ARM)	39m 58s
Build ARM binary (self-hosted, Linux, ARM64, aarch64-linux-ghcup, 9.2.6, ARM64)	16m 40s
Build linux binary (ubuntu-latest, i386-linux-ghcup, 8.10.7, 32)	17m 20s
Build linux binary (ubuntu-latest, x86_64-linux-ghcup, 8.10.7, 64)	29m 51s
Build binary (Mac/Win) (self-hosted, macOS, ARM64, aarch64-apple-darwin-ghcup, 9.2.6, ARM64)	24m 38s
Build binary (Mac/Win) (macOS-11, x86_64-apple-darwin-ghcup, 9.2.6, 64)	33m 39s
Build binary (Mac/Win) (windows-latest, x86_64-mingw64-ghcup, 8.10.7, 64)	23m 46s
hls	27m 59s
Test linux (ubuntu-latest, i386-linux-ghcup, 8.10.7, 32, Alpine)	3m 11s
Test linux (ubuntu-latest, x86_64-linux-ghcup, 8.10.7, 64, Alpine)	3m 8s
Test linux (ubuntu-latest, x86_64-linux-ghcup, 8.10.7, 64, Ubuntu)	7m 6s
Test Mac/Win (self-hosted, macOS, ARM64, aarch64-apple-darwin-ghcup, 9.2.6, ARM64, na)	6m 12s
Test Mac/Win (macOS-11, x86_64-apple-darwin-ghcup, 9.2.6, 64, na)	18m 35s
Test Mac/Win (windows-latest, x86_64-mingw64-ghcup, 8.10.7, 64, na)	11m 22s
Test ARM (self-hosted, Linux, ARM64, armv7-linux-ghcup, 9.2.2, ARM, Ubuntu)	6m 12s
Test ARM (self-hosted, Linux, ARM64, aarch64-linux-ghcup, 9.2.6, ARM64, Ubuntu)	6m 10s
release	0s
	4h 35m 47s

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