[DisplayList] Remove unnecessary DisplayListBuilder as DlOpReceiver accesses (#54969)

Fixes flutter/flutter#144070

There is a mechanism by which you can access a DisplayListBuilder as if it were a DlOpReceiver for dispatching one DisplayList into another.

This mechanism also resembles the legacy way in which one would write graphics snippets prior to the creation of the DlCanvas interface and so we have dozens of old unit tests which were written to test the Builder class by filling it with commands in the Receiver/Dispatcher format. This type of access is obsolete and maintaining the ability for arbitrary code to talk to a Builder in that manner is getting in the way of future work.

This PR rewrites over 100 of such unit tests to use the standard DlCanvas-style interface to record operations into a Builder, leaving only a dozen or so cases of internal state tests that still inject ops directly to test the internal state keeping.

Author: flar