This moves some fields and methods from the WasmRunner template to the
WasmRunnerBase base class. This avoids repeated compilation for the
different instantiations of the WasmRunner template.

Additional changes:
- SetUpTrapCallback, SetThreadInWasmFlag, and ClearThreadInWasmFlag are
  static now.
- CheckUsedExecutionTier is unused, and did not even compile any more.
  In the template class this was OK, because it's only compiled on first
  use.

R=thibaudm@chromium.org

Change-Id: I485729cf4a1fd93fe6abb0be269694f0179fc4ea
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593331Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71781}