This is a reland of ac654646.
Two constants defined in {AssemblerBase} were not defined anywhere,
which is fixed now.

Original change's description:
> [wasm] Remove WasmInstructionBuffer
>
> {WasmInstructionBuffer} was basically a wrapper around {AssemblerBuffer}
> which remembered the last {AssemblerBuffer} on {Grow()}. Since the
> {Assembler} itself already keeps track of the latest {AssemblerBuffer},
> this functionality is mostly redundant. All we need instead is a method
> to retrieve the {AssemblerBuffer} from the {Assembler}.
>
> This CL thus removes {WasmInstructionBuffer} and instead adds
> {AssemblerBase::ReleaseBuffer}.
>
> R=jkummerow@chromium.org, mslekova@chromium.org
> CC=dlehmann@google.com
>
> Bug: v8:11714
> Change-Id: Id07945b67992802a6177bf09e5f5c5be08f657b0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2982013
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Maya Lekova <mslekova@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#75336}

Bug: v8:11714
Change-Id: I8797de1a7a78a93aaef936e46bfd1e73ec2cc9d5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2982015Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75338}