[dart2wasm] Incorrect default type arguments passed in dynamic invocations

[osa1]

Currently runtime type of functions (_FunctionType) has a field for type parameter bounds (TypeParameter.bound in kernel), but not for type parameter default values (TypeParameter.defaultType in kernel).

So when we have a dynamic invocation of a generic function and no type arguments are passed we're using the bounds as defaults, but bounds and defaults are not always the same. We should add TypeParameter.defaultTypes of generic functions to _FunctionType and use those when type parameters are missing in dynamic invocations.

[osa1]

WIP CL: https://dart-review.googlesource.com/c/sdk/+/283022