Precompile shipit assets before benchmark iterations #1793

Job	Run time
benchmark-run-once	1m 40s
benchmark-graph	50s
benchmark-ractor-only (head)	40s
test (ruby)	1m 2s
benchmark-ractor (head)	6m 39s
benchmark-default (head)	13m 10s
benchmark-default (ruby)	11m 45s
test (head)	1m 7s
test (truffleruby)	1m 58s
benchmark-default (truffleruby, --excludes=knucleotide,lobsters,ruby-lsp,shipit)	13m 31s
all-tests	4s
	52m 26s

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