Add support for yield statement

Implement visitYield.

Fixes #489

from ntkoopman:yield b46d1f0

COPYBARA_INTEGRATE_REVIEW=#489
PiperOrigin-RevId: 314633394

Author: ntkoopman

core/src/main/java/com/google/googlejavaformat/java/java14/Java14InputAstVisitor.java

@@ -60,7 +60,11 @@ public Void visitBindingPattern(BindingPatternTree node, Void unused) {
   @Override
   public Void visitYield(YieldTree node, Void aVoid) {
     sync(node);
-    return super.visitYield(node, aVoid);
+    token("yield");
+    builder.space();
+    scan(node.getValue(), null);
+    token(";");
+    return null;
   }
 
   @Override

core/src/test/resources/com/google/googlejavaformat/java/testdata/ExpressionSwitch.input

@@ -6,4 +6,23 @@ class ExpressionSwitch {
       default -> odd(x - 1);
     };
   }
-}
+
+  {
+    int f = switch (i) {
+      case 0 -> 0;
+      default -> {
+        yield n / i;
+      }
+    };
+
+    int g = switch (i) {
+      case 0: yield 0;
+      default: yield n/i;
+    };
+
+    switch (i) {
+      case 0 -> { System.out.println("0"); }
+      default -> System.out.println("default");
+    }
+  }
+}

core/src/test/resources/com/google/googlejavaformat/java/testdata/ExpressionSwitch.output

@@ -6,4 +6,29 @@ class ExpressionSwitch {
       default -> odd(x - 1);
     };
   }
+
+  {
+    int f =
+        switch (i) {
+          case 0 -> 0;
+          default -> {
+            yield n / i;
+          }
+        };
+
+    int g =
+        switch (i) {
+          case 0:
+            yield 0;
+          default:
+            yield n / i;
+        };
+
+    switch (i) {
+      case 0 -> {
+        System.out.println("0");
+      }
+      default -> System.out.println("default");
+    }
+  }
 }