This CL is pretty mechanical; I just iterated through some Torque
classes making the following changes:

- Use @generateCppClass if it seems easy to
- Use @generatePrint if the existing printer doesn't do anything special
- Fix up any imprecise field types

It also includes two minor changes to implementation-visitor:

- Add a new -inl.h file with the things needed for
  torque-generated/class-definitions-tq.cc so we don't need to keep
  changing the compiler when we add @generateCppClass.
- Avoid emitting incorrect accessors for ExternalPointers. This isn't
  strictly necessary for correctness, as the accessors defined in C++
  already hide the ones inherited from generated code, but it makes me
  feel safer.

Change-Id: I4d5a8ba6f86ebff57a0d147619212a3993b087c0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2185824Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#67719}