We have two constants for the PC load delta; this CL
consolidates them into one. The CL does not change MIPS
as the two constants are defined to different values there.

Bug: v8:6666
Change-Id: If207a59dea3ef33756a5d7330217ab8a176bdf63
Reviewed-on: https://chromium-review.googlesource.com/1161926Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54898}