Check whether a trampoline pool should be emitted after unblocking.
Otherwise, back-to-back sequences which block the trampoline pool can
cause it to be out of reach.

R=joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1433343002

Cr-Commit-Position: refs/heads/master@{#31945}