x86 microcode loading and misc fixes #1195

Job	Run time
build-minimal-sysroots (x86_64)	58s
build-minimal-sysroots (riscv64)	1m 18s
build-minimal-sysroots (arm64)	57s
build-toolchains (ubuntu-latest, x86_64, gnu)	32s
build-toolchains (ubuntu-latest, riscv64, gnu)	43s
build-toolchains (ubuntu-latest, arm64, gnu)	37s
build-toolchains (ubuntu-20.04, x86_64, gnu)	30s
build-toolchains (ubuntu-20.04, riscv64, gnu)	42s
build-toolchains (ubuntu-20.04, arm64, gnu)	28s
build-toolchains (ubuntu-latest, llvm, all)	1m 6s
build-llvm	3m 15s
build	2m 55s
build-llvm-arm64	0s
build-arm64	0s
build-riscv	3m 3s
build-llvm-riscv64	2m 36s
run-x86_64	0s
run-riscv	0s
run-riscv64-llvm	0s
run-x86_64-llvm	0s
	19m 40s

Provide feedback