The spec was normatively changed to simplify var scopes for parameter
expressions. Previously there was a per-parameter var scope in sloppy
mode so direct evals could introduce vars that did not escape the
parameter position. That semantics is complex both for the programmer
and implementation and has resulted in bugs in the past. Furthermore, it
has never been fully interoperable (with Safari in particular). The spec
was instead changed to be simpler: to have a single var scope for
sloppy evals in parameters that encloses the parameter scope and body
scope.

This simplification lets us remove expression-scope-reparenter.

Drive-by removal of stale reference to PatternRewriter.

Bug: v8:7532
Change-Id: Iade5594abe0009f7f3f6a1adad18628b17e1e779
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1962471Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65517}