CodeGen: Cast temporary variable to proper address space

In C++ all variables are in default address space. Previously change has been
made to cast automatic variables to default address space. However that is
not sufficient since all temporary variables need to be casted to default
address space.

This patch casts all temporary variables to default address space except those
for passing indirect arguments since they are only used for load/store.

This patch only affects target having non-zero alloca address space.

Differential Revision: https://reviews.llvm.org/D33706

llvm-svn: 305711