In order to clarify the difference between, e.g., InstructionStart and
instruction_start, rename as follows:

Code::instruction_start -> raw_instruction_start
Code::instruction_end   -> raw_instruction_end
Code::instruction_size  -> raw_instruction_size

The difference between the camel-case and raw_* function families is
in how they handle off-heap-trampoline Code objects. For example, when
called on an off-heap-trampoline: raw_instruction_start returns the
trampoline's entry point, while InstructionStart returns the off-heap
code's entry point (located in the .text section of the binary).

Some callsites were updated to call the camel-case function family as
appropriate.

Bug: v8:6666
Change-Id: I4a572f47c2d161a853599d7c17879e263b0d1a87
Reviewed-on: https://chromium-review.googlesource.com/997532
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52387}