+scr additional functions for tagging issues on github
=act #15165 should fix out-of-bounds in actor creation
Other than that, also improved failure logging when AIOOB happens in the histogram
Added a test which shows why the updateWithExpectedInterval method
should be preferred too.

Backport from master

Conflicts:
	akka-testkit/src/test/scala/akka/testkit/metrics/reporter/AkkaGraphiteReporter.scala