This CL splits the class definitions per .tq file, to realize the
following relationship:
A class defined in src/objects/foo.tq has a C++ definition in
src/objects/foo.h. Torque then generates:

- torque-generated/src/objects/foo-tq.inc
  An include file (no proper header) to be included in src/objects/foo.h
  containing the Torque-generated C++ class definition.

- torque-generated/src/objects/foo-tq-inl.inc
  An include file (no proper header) to be included in
  src/objects/foo-inl.h containing inline function definitions.

- torque-generated/src/objects/foo-tq.cc
  A source file including src/objects/foo-inl.h that contains non-inline
  function definitions.

Advantages of this approach:
- Avoid big monolithic headers and preserve the work that went into
  splitting objects.h
- Moving a definition to Torque keeps everything in the same place
  from a C++ viewpoint, including a fully Torque-generated C++ class
  definition.
- The Torque-generated include files do not need to be independent
  headers, necessary includes or forward declarations can just be added
  to the headers that include them.

Drive-by changes:
A bunch of definitions and files had to be moved or created to realize
a consistent 1:1 relationship between .tq files and C++ headers.


Bug: v8:7793
TBR: hpayer@chromium.org
Change-Id: I239a89a16d0bc856a8669d7c92aeafe24a7c7663
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2470571
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#70853}