This is one of the first steps at moving to replace target-dependent

intrinsics with target-indepdent intrinsics.  The first instruction(s) to be 
handled are the vector versions of count leading zeros (ctlz).

The changes here are to clang so that it generates a target independent 
vector ctlz when it sees an ARM dependent vector ctlz.  The changes in llvm 
are to match the target independent vector ctlz and in VMCore/AutoUpgrade.cpp 
to update any existing bc files containing ARM dependent vector ctlzs with 
target-independent ctlzs.  There are also changes to an existing test case in 
llvm for ARM vector count instructions and a new test for the bitcode upgrade.

<rdar://problem/11831778>

There is deliberately no test for the change to clang, as so far as I know, no
consensus has been reached regarding how to test neon instructions in clang;
q.v. <rdar://problem/8762292>

llvm-svn: 160200