Fix SelectionDAGBuilder::getDbgValue to not expect DW_OP_deref on FI vars

This fixes an oversight in r300522, which changed alloca
dbg.values to no longer emit a DW_OP_deref.

The array.ll testcase was regenerated from source.

Fixes PR33166:
https://bugs.llvm.org/show_bug.cgi?id=33166

llvm-svn: 303897