Modifies the serialization strategy used for dynamic modules. Emits 2 dill files, main.dill and main.opt.dill.
main.dill serialized before TFA runs and is used by the CFE to compile the dynamic module faster (it doesn't have to recompile the main module libraries from source).
main.opt.dill is serialized at the end of the compilation of the main module and contains a copy of all the main module libraries after TFA. This dill is used by dart2wasm to produce consistent references into the main module.
Also emit new record classes into a distinct library so that all downstream code will appropriately emit the new code without special logic.
Change-Id: Idf7a87d2014dad513c753330743f753312aa472f
Tested: Just updating signature, no testing needed.
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/422342
Reviewed-by: Martin Kustermann <kustermann@google.com>
Nate Biggs
b3e7e2fbbd