Initial tap is missing sometimes; either its never delivered or it is
delivered before gesture controller is hooked up.
1: Update MemoryTest to have option `requiresTapToStart` guarding the
new paths
2: Update the two perf tests that appear to be flaky to output when
TAPPED is received
3: Update the MemoryTest to keep tapping while waiting for TAPPED
Tested on devicelab:
* setting iterations=1
* removing the timeout before READY
* running tests in a while loop
Before this change, you could get the test to hang often. After this
change you'll see "tapping device... [x]" where x is the counter.
Fixes https://github.com/flutter/flutter/issues/150096
e80bbd929e