Warn when two executables have the same revision and flags #1818

Job	Run time
test (truffleruby)	1m 53s
benchmark-run-once	1m 36s
benchmark-ractor (head)	6m 42s
test (ruby)	59s
benchmark-graph	46s
test (head)	59s
benchmark-default (head)	12m 13s
benchmark-ractor-only (head)	38s
benchmark-default (truffleruby, --excludes=knucleotide,lobsters,ruby-lsp,shipit)	13m 20s
benchmark-default (ruby)	11m 37s
all-tests	2s
	50m 45s

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