loadtest: prepare for multiple consecutive runs #1497

Job	Run time
cross compilation	4m 16s
Docker build check	4m 8s
Format check	35s
Compilation check	34s
run itests	5m 38s
run itests postgres	9m 15s
Lint check	2m 45s
go mod check	1m 10s
RPC check	1m 44s
Sqlc check	40s
test vector check	1m 8s
run unit tests (unit-race)	7m 10s
run unit tests (unit-cover)	1m 51s
run unit tests (unit dbbackend=postgres)	5m 25s
	46m 19s

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