Some tools that transform Wasm today, already support encoding the
transforms and correctly updating locations in source maps, but not yet
in DWARF (although this is being worked on).

Until they catch up, it's best to consistently prefer source maps over
DWARF when both are present, and not just rely on order of sections as
accidentally done in the previous CL that introduced DWARF info.

Ref: crrev.com/c/v8/v8/+/1834341
Bug: chromium:1016772
Change-Id: I769311e2096ae0e4ca304bef0a0453c7e0776aae
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1888930
Commit-Queue: Ingvar Stepanyan <rreverser@google.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64647}