[AST] Print "__owned" and "__shared" with leading underscores

The type printer was being optimistic about these, but that's a
problem for testing textual interfaces right now.

Author: jrose-apple

lib/AST/TypeRepr.cpp

@@ -572,10 +572,10 @@ void SpecifierTypeRepr::printImpl(ASTPrinter &Printer,
     Printer.printKeyword("inout");
     break;
   case TypeReprKind::Shared:
-    Printer.printKeyword("shared");
+    Printer.printKeyword("__shared");
     break;
   case TypeReprKind::Owned:
-    Printer.printKeyword("owned");
+    Printer.printKeyword("__owned");
     break;
   default:
     llvm_unreachable("unknown specifier type repr");

test/ModuleInterface/smoke-test.swift

@@ -1,8 +1,10 @@
 // RUN: %target-swift-frontend -emit-interface-path - -emit-module -o /dev/null %s | %FileCheck %s
-// RUN: %target-swift-frontend -emit-interface-path - -emit-module -o /dev/null %s %S/Inputs/other.swift | %FileCheck -check-prefix CHECK-MULTI-FILE %s
+// RUN: %target-swift-frontend -emit-interface-path - -emit-module -o /dev/null %s %S/Inputs/other.swift | %FileCheck -check-prefix CHECK -check-prefix CHECK-MULTI-FILE %s
 
 // CHECK: public func verySimpleFunction(){{$}}
-// CHECK-MULTI-FILE: public func verySimpleFunction(){{$}}
 public func verySimpleFunction() {}
 
+// CHECK: public func ownership(_ x: __shared AnyObject){{$}}
+public func ownership(_ x: __shared AnyObject) {}
+
 // CHECK-MULTI-FILE: public func otherFileFunction(){{$}}