In the process add missing base	Torque functionality for 8-bit and
16-bit integers and Cast<> operators to make them easy to use.

As a poster child, port the field declarations of SharedFunctionInfo
to the class definition in base.tq.

As a drive by: Add the missing GN dependency on
class-definitions-from-dsl.h

Bug: v8:7793
Change-Id: I76a41c2e81ffd1cbb90ac7a4ef8d4003ac86e8dc
Reviewed-on: https://chromium-review.googlesource.com/c/1445882Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Daniel Clifford <danno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59321}