Move tracker comments back to `innerComments`

[overlookmotel]

As workaround for babel/babel#15138, 1b27938 moves tracker comments on functions and classes to leadingComments on function/class id, params or body. Previously comments were placed as innerComments on the function/class itself.

This is largely fine, but these tracker comments should always be the first comments in the function, and small chance that an "inner" comment in source code could get output before it.

Once babel/babel#15138 is fixed, revert 1b27938 to put tracker comments in innerComments again.