Printing regexp code used to behind the generic --print-code flag, but
there was no way to distinguish between irregexp-generated code; and
printing regexp bytecode was not supported at all (the
--trace-regexp-bytecodes flag *did* exist, but prints the execution
trace at runtime and not the generated bytecode sequence).

This CL adds two new flags:

--print-regexp-code
--print-regexp-bytecode

Regexp code is no longer printed as part of --print-code.

Example output for --print-regexp-bytecode:

generated bytecode for regexp pattern: .(?<!^.)
0x1ddcc614cbd0     0  PUSH_BT, 02, 00, 00, 00, c0, 00, 00, 00 .......
0x1ddcc614cbd8     8  LOAD_CURRENT_CHAR, 11, 00, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbe0    10  CHECK_CHAR, 18, 0a, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbe8    18  CHECK_CHAR, 18, 0d, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbf0    20  PUSH_CP, 01, 00, 00, 00 ...

Bug: chromium:996391
Change-Id: I731defbd7cf9ed29753a39bb1d7205dc136ca950
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1773249
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63442}