Port commit 23dbb81d.

Original CL message:

>This CL uses pc-relative jumps and calls (B/BL) for calls from embedded
>builtins to embedded builtins. To make this work, the code range size is
>limited to 32MB on arm during mksnapshot, which ensures that all builtin
>to builtin offsets for jumps/calls fit into the B/BL immediate. At code
>generation time, we put a placeholder into the instruction offset which
>we resolve to the right code object when the code is copied to the heap.
>We use a new relocation mode RELATIVE_CODE_TARGET for these relative jumps.
>The relocation mode RELATIVE_CODE_TARGET should never appear after
>generating the snapshot.
>
>We modify the target_address/set_target_address methods of RelocInfo
>such that they return the absolute target addresses for pc-relative B/BL
>instructions. This ensures that the GC can treat RELATIVE_CODE_TARGET in
>the same way as code targets. This, however, only matters during
>snapshot creation time, and production code never contains
>RELATIVE_CODE_TARGET relocations.
>
>Bug: v8:6666
>Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
>Change-Id: If7eab83ad588859ca87c654a5ddc3e37caea884c
>Reviewed-on: https://chromium-review.googlesource.com/1117181
>Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
>Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
>Reviewed-by: Jakob Gruber <jgruber@chromium.org>
>Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
>Cr-Commit-Position: refs/heads/master@{#54320}

This CL is completed Miran's draft without MIPS64 port.
(https://chromium-review.googlesource.com/c/v8/v8/+/1136640/3).

Change-Id: I979378ac445548641755968d890f7f4a82dc7986
Reviewed-on: https://chromium-review.googlesource.com/c/1221313
Commit-Queue: Ivica Bogosavljevic <ibogosavljevic@wavecomp.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ivica Bogosavljevic <ibogosavljevic@wavecomp.com>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56640}