This is a reland of bf3d7b9a

Original change's description:
> [wasm] Store compile errors in CompilationState
> 
> We are currently storing compilation errors in the individual
> compilation units and pass it to the ErrorThrower during finishing.
> This CL changes that to store errors on the CompilationState directly.
> From there, it is propagated to the ErrorThrower in the compilation
> state callback.
> This removes more work from the finisher task and slims down the
> WasmCompilationUnits.
> 
> R=mstarzinger@chromium.org
> 
> Bug: v8:8343, v8:7921
> Change-Id: Id332add43d4219d2a30fee653ed4e53a9b2698d9
> Reviewed-on: https://chromium-review.googlesource.com/c/1303720
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#57091}

Bug: v8:8343, v8:7921
Change-Id: Iaa5c89d224cb2bcfca2d12eba305413a9ad95618
Reviewed-on: https://chromium-review.googlesource.com/c/1304547
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57126}