Add loadtest `sendV2` #3785

Job	Run time
Docker build check	3m 37s
Compilation check	1m 38s
cross compilation	12m 10s
Format check	25s
run itests	12m 14s
run itests postgres	20m 7s
migration version check	12s
Lint check	2m 48s
go mod check	24s
RPC check	1m 17s
run LiT tests	15m 38s
sample configuration check	39s
Sqlc check	2m 49s
test vector check	1m 0s
run unit tests (unit-race)	14m 53s
run unit tests (unit-cover)	4m 44s
run unit tests (unit dbbackend=postgres)	6m 19s
finish	2s
	1h 40m 56s

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