[attributes] Extend os_returns_(not_?)_retained attributes to parameters

[attributes] Extend os_returns_(not_?)_retained attributes to parameters

When applied to out-parameters, the attributes specify the expected lifetime of the written-into object.

Additionally, introduce OSReturnsRetainedOn(Non)Zero attributes, which
specify that an ownership transfer happens depending on a return code.

Differential Revision: https://reviews.llvm.org/D56292

llvm-svn: 350942