swift234

SILGen: Clean up lvalue re-abstraction a bit

When we emit calls to getters and setters with emitApply(), the call
emission code ends up re-abstracting the result of a getter or the
parameter to a setter.

As a result, getOrigFormalType() was incorrect for logical path
components. This was worked around by only adding an OrigToSubst
path component to an lvalue if the last path component was physical.

This caused a problem in the following case:

1) There was an abstraction difference between the storage of the
   protocol requirement and the storage of the protocol witness

2) There was an abstraction difference between the storage of the
   protocol witness, and the fully-substituted type of the witness

An example is when the witness is in a protocol extension, and uses
'Self' or some other associated type which is concrete and loadable
in the conformance.

Fix this properly by splitting up getStorageTypeData() into two
functions, one used when adding physical path components and another
one used for logical.

As a result, we can now give the correct abstraction pattern to
logical path components.