Fix printing of C style casts with suppressed specifiers

[nick.sumner]

Summary

Allow C style casts to be printed correctly even when the incoming
PrintingPolicy suppresses specifiers. This can happen, for instance,
when casts occur during the initialization of variables inside a
DeclGroup. Given the code:
void foo() {

int *x = ((void *)0), *y = ((void *)0);

}

The casts are printed as:
int *x = ((void *)0), *y = ((*)0);

Note that the second cast lacks 'void' because specifiers are
suppressed when printing members of the declgroup (after the first).

With the patch, the casts are printed as:
int *x = ((void *)0), *y = ((void *)0);

lib/AST/StmtPrinter.cpp

 
 void StmtPrinter::VisitExtVectorElementExpr(ExtVectorElementExpr *Node) {
   PrintExpr(Node->getBase());
   OS << ".";
   OS << Node->getAccessor().getName();
 }
 void StmtPrinter::VisitCStyleCastExpr(CStyleCastExpr *Node) {
   OS << '(';
-  Node->getTypeAsWritten().print(OS, Policy);
+  PrintingPolicy SubPolicy(Policy);
+  SubPolicy.SuppressSpecifiers = false;
+  Node->getTypeAsWritten().print(OS, SubPolicy);
   OS << ')';
   PrintExpr(Node->getSubExpr());
 }
 void StmtPrinter::VisitCompoundLiteralExpr(CompoundLiteralExpr *Node) {
   OS << '(';
   Node->getType().print(OS, Policy);
   OS << ')';
   PrintExpr(Node->getInitializer());

test/Sema/ast-print.c

 
 struct pair_t {
   int a;
   int b;
 };
 
 // CHECK: struct pair_t p = {a: 3, .b = 4};
 struct pair_t p = {a: 3, .b = 4};
+
+void cast() {
+// CHECK: int *x = ((void *)0), *y = ((void *)0);
+  int *x = ((void *)0), *y = ((void *)0);
+}