[OpenMP] Parsing + sema for target parallel directive.

Summary:
This patch adds parsing + sema for the target parallel directive and its clauses along with testcases.

Reviewers: ABataev

Differential Revision: http://reviews.llvm.org/D16553

Rebased to current trunk and updated test cases.

llvm-svn: 258832
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 10bec39..47c7ab2 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -2343,6 +2343,7 @@
   void EmitOMPTargetDataDirective(const OMPTargetDataDirective &S);
   void EmitOMPTargetEnterDataDirective(const OMPTargetEnterDataDirective &S);
   void EmitOMPTargetExitDataDirective(const OMPTargetExitDataDirective &S);
+  void EmitOMPTargetParallelDirective(const OMPTargetParallelDirective &S);
   void EmitOMPTeamsDirective(const OMPTeamsDirective &S);
   void
   EmitOMPCancellationPointDirective(const OMPCancellationPointDirective &S);