@effects is too low a level, and not meant for general usage outside
the standard library. Therefore it deserves to be underscored like
other such attributes.
Specifically, do not perform the early inlining for functions annotated with @_semantics("pair_no_escaping_closure") and @_semantics("self_no_escaping_closure")
Add new tests and cleanup some tests.
It recovers from the performance regression that was recently introduced.
Fixes rdar://32555803
