Check looks at the currently-running goroutines and checks if there are any
interestring (created by gRPC) goroutines leaked. It waits up to 10 seconds
in the error cases.
RegisterIgnoreGoroutine appends s into the ignore goroutine list. The
goroutines whose stack trace contains s will not be identified as leaked
goroutines. Not thread-safe, only call this function in init().