dart2js should throw TypeErrorImplementation for both Cast and Type errors

[leafpetersen]

Per #40763, I landed the change to make the dart2js implementation classes TypeErrorImplementation and CastErrorImplementation both implement TypeError and CastError here.

CastError will be deprecated in a follow up CL. The web compilers should be changed to throw instances of a single implementation class (TypeErrorImplementation) for all implicit and explicit casts. This change should be non-breaking given the changes in my CL.

cc @sigmundch @rakudrama @fishythefish @nshahan

[rakudrama]

js_runtime now has a single _TypeError class that implements both TypeError and CastError interfaces.

js_dev_runtime has two 'Impl' classes, both implementing TypeError and CastError.
@nshahan perhaps these could be merged.

[nshahan]

I'll take a look. Since this has already been done in dart2js I'll reassign the issue.

[nshahan]

All uses of CastErrorImpl were already migrated to TypeErrorImpl in https://dart-review.googlesource.com/c/sdk/+/139490. I'm sending out a change to finally delete CastErrorImpl and close this issue.