... to minimize pollution of v8::internal namespace.
This CL also removes usages of WriteBarrierKind from CodeAssembler interface.

Bug: v8:9183
Change-Id: I7e87c0a98cfd08b3740a022cf12d3aab415da67a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1599176
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61301}