LRU/reclamation work #1051

Job	Run time
build-minimal-sysroots (x86_64)	48s
build-minimal-sysroots (riscv64)	1m 19s
build-minimal-sysroots (arm64)	1m 8s
build-toolchains (ubuntu-latest, x86_64, gnu)	39s
build-toolchains (ubuntu-latest, riscv64, gnu)	34s
build-toolchains (ubuntu-latest, arm64, gnu)	24s
build-toolchains (ubuntu-20.04, x86_64, gnu)	53s
build-toolchains (ubuntu-20.04, riscv64, gnu)	34s
build-toolchains (ubuntu-20.04, arm64, gnu)	42s
build-toolchains (macos-latest, x86_64, gnu)	1m 2s
build-toolchains (macos-latest, riscv64, gnu)	1m 6s
build-toolchains (macos-latest, arm64, gnu)	46s
build-toolchains (ubuntu-latest, llvm, all)	1h 45m 13s
build-llvm-riscv64	2m 35s
build-arm64	3m 15s
build-llvm	3m 21s
build	3m 21s
build-llvm-arm64	2m 31s
build-riscv	3m 3s
run-riscv	0s
run-riscv64-llvm	0s
run-x86_64	0s
run-x86_64-llvm	0s
	2h 13m 14s

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