Now that CodeAssembler uses optimizing TurboFan passes, creating
constants without using the caching implemented in JSGraph leads to
problems, since value numbering only works properly if all constants
in the graph were introduced through the cache.
To mitigate this, this CL creates the JSGraph earlier so that
CodeAssembler can already use the same JSGraph used by later TurboFan
optimizations.
For other uses of RawMachineAssembler, everything stays as before.

This issue is creating bot failures in
https://chromium-review.googlesource.com/c/v8/v8/+/1958011

Change-Id: Ife017876b19cb2602694279ef1da75f23e18a031
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1967329Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65477}