8226510: No compilation error when switch expression has no result expressions

Ensure a compile-time error is produced when there are no result expressions in an switch expression.

Reviewed-by: vromero

test/langtools/tools/javac/diags/examples/ContinueOutsideSwitchExpression.java

@@ -30,7 +30,8 @@ class ContinueOutsideSwitchExpression {
     int t(int i) {
         OUT: while (true) {
             return switch (i) {
-                default: continue OUT;
+                case 0: continue OUT;
+                default: yield 0;
             };
         }
     }