This commit attempts to change as little behavior as possible, but it
does require reordering the fields within Map to abide by Torque rules
specifying that strong and weak fields must be in separate sections.

Also includes some Torque compiler updates:
- Allow enums (types extending from integral types) as class fields
- Rename @ifdef to @if and add @ifnot for inverse checks
- Allow void fields in class declarations, which take up no space and
  emit no accessors

Bug: v8:8952
Change-Id: I1de6f34c1b15ed87d718666a05176980a218e97c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1480919
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61588}