[wasm] Initialize CompilationUnits based on the compilation progress

In the existing code we calculate twice how we want to compile a
WebAssembly function, first in InitializeCompilationProgress, and then
again in InitializeCompilationUnit. With this CL we use the information
in the compilation progress to create the CompilationUnits. Not only
does this make the code cleaner, it will also allow us to initialize the
compilation progress differently for deserialization but reuse the code
to create CompilationUnits.

R=clemensb@chromium.org

Bug: v8:11862
Change-Id: Iee48727be429e3a3a950404806fdd04264145999
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2988759
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75516}