[OPENMP]Allow cancellation constructs in target parallel regions.

Summary:
omp cancellation point parallel and omp cancel parallel directives are
allowed in target paralle regions.

Reviewers: jdoerfert

Subscribers: yaxunl, guansong, caomhin, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78941
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index b7e46bc..fc96cff 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -2336,6 +2336,7 @@
   VisitStmt(D);
   Record.push_back(D->getNumClauses());
   VisitOMPExecutableDirective(D);
+  Record.writeBool(D->hasCancel());
   Code = serialization::STMT_OMP_TARGET_PARALLEL_DIRECTIVE;
 }