The use of jalr ra is unpredictable if instruction in branch delay slot
is in next page.

This finally fixes random failures in JS debugger and InteruptRequest tests.

TEST=mjsunit/debug-*,
     cctest/test-api/RequestInterruptTestWithNativeAccessor
BUG=

Review URL: https://codereview.chromium.org/1220443002

Cr-Commit-Position: refs/heads/master@{#29331}