Apply return result type check to all function implementations.

[MikeStall]

Functions implemented via AsyncFunctionPtr have an additional type check on the return result. This chekc ought to be apply to all implementations.

https://github.com/microsoft/Power-Fx/blob/0fa19687742caa771c4a8f0716f07005497bec49/src/libraries/Microsoft.PowerFx.Interpreter/EvalVisitor.cs#L398

It fails on some, including these:

• AsTypeIsTypeParseJSONTests.cs ,
• BlobTests.cs line
• ValidateNoRecordToRecordAggregateCoercionCurrencyth