This is the first step in process of replacing JR and JALR instructions
with JIC and JIALC for r6. Trampoline in r6 now uses JIC. Also
BranchLong and BranchAndLinkLong MacroAssembler functions now use JIC
and JIALC in r6 if branch delay slot is not used.

BUG=

Review URL: https://codereview.chromium.org/1573983002

Cr-Commit-Position: refs/heads/master@{#34236}