Reason for revert:
Fails on gc-stress.
Original issue's description:
> [wasm][asm.js] Fix and enable several asm.js tests with the new parser.
>
> Fix a few items broken during review of scanner + parser:
> * Make the scanner retain stale newline state on a rewind (as otherwise it must be able to correctly rewind that too, though it doesn't need it). (Probably should revisit).
> * Change StashCode in the builder skip to the zero case, as it crashes for some reason (added TODO).
>
> Also fix:
> * Drop test based on constant expression evaluation in main parser
> * Support constant defined based on existing constant.
> * Type constants as signed.
> * Added a check that all used functions are defined eventually.
> * Zone allocate strings for simplicity (TODOs to refactor better).
>
> BUG=v8:6090
> BUG=v8:4203
> R=mstarzinger@chromium.org,marja@chromium.org,vogelheim@chromium.org
>
> Review-Url: https://codereview.chromium.org/2771183002
> Cr-Commit-Position: refs/heads/master@{#44200}
> Committed: be0dbdd679TBR=clemensh@chromium.org,bradnelson@google.com,marja@chromium.org,mstarzinger@chromium.org,vogelheim@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6090
Review-Url: https://codereview.chromium.org/2782613002
Cr-Commit-Position: refs/heads/master@{#44201}
f8973f1caa