[Lint] Don't warn about passing alloca'd value to tail call if using byval

Summary:
This fixes PR35241.

When using byval, the data is effectively copied as part of the call
anyway, so the pointer returned by the alloca will not be leaked to the
callee and thus there is no reason to issue a warning.

Reviewers: rnk

Reviewed By: rnk

Subscribers: Ka-Ka, llvm-commits

Differential Revision: https://reviews.llvm.org/D40009

llvm-svn: 318279