Inherit properties in function from method in loose mode

[rubennorte]

Q	A
Patch: Bug Fix?	Yes
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	There was a test for this and keeps passing
Documentation PR Link
Any Dependency Changes?	No
License	MIT

This modifies the class transform to inherit the properties from methods to the function that's generated in loose mode.

There was a test to ensure the return type was copied to the new function, but the loc of the node was lost because it was copied manually instead of using inherits.

This is tested in packages/babel-plugin-transform-classes/test/fixtures/loose/method-return-type-annotation and the test keeps passing.

Perhaps I should add a test for the location, but so far all tests for the package only check input/output, not the node state.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/9558/

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/9558/

[nicolo-ribaudo]

It's ok without tests, but I think there could be many other places where we don't copy the location.