[OpenMP] Support for thread_limit-clause on the 'target teams' directive.

The thread_limit-clause on the combined directive applies to the
'teams' region of this construct. We modify the ThreadLimitClause
class to capture the clause expression within the 'target' region.

Reviewers: ABataev
Differential Revision: https://reviews.llvm.org/D29087

llvm-svn: 293049
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index ce136bf..04f414e 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -2306,6 +2306,7 @@
 }
 
 void OMPClauseReader::VisitOMPThreadLimitClause(OMPThreadLimitClause *C) {
+  VisitOMPClauseWithPreInit(C);
   C->setThreadLimit(Reader->Record.readSubExpr());
   C->setLParenLoc(Reader->ReadSourceLocation());
 }