[ linear ] add concurrently #1183

Job	Run time
initialise	5s
quick-check	5m 37s
ubuntu-bootstrap-racket	12m 35s
macos-bootstrap-chez	5m 52s
nix-bootstrap-chez	17m 54s
ubuntu-bootstrap-chez	7m 49s
ubuntu-self-host-previous-version	10m 27s
windows-bootstrap-chez	24m 21s
macos-self-host-chez	23m 16s
ubuntu-self-host-chez	10m 9s
ubuntu-build-api	4m 15s
ub-test-elab-util	39s
ub-test-collie	21s
ub-pack-test-lsp	14m 52s
ub-pack-test-pack	12m 48s
ub-test-frex	3m 47s
ub-test-katla-and-html	5m 40s
ubuntu-self-host-racket	0s
windows-self-host-racket	13m 8s
	2h 53m 35s

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