[jdk13] support for switch expression's yield keyword.

test/pretty/resource/after/Switch13.java

@@ -0,0 +1,55 @@
+public class Switch13 {
+	public void basic() {
+		switch (5) {
+		case 1: 
+		case 2: 
+			System.out.println("OK");
+			break;
+		default: 
+		}
+	}
+
+	public void multiCase() {
+		switch (5) {
+		case 1, 2: 
+			System.out.println("OK");
+		default: 
+		}
+	}
+
+	public int switchExpr1() {
+		return switch (5) {
+			case 1, 2 -> 0;
+			case 3 -> {
+				yield 10;
+			}
+			default -> 10;
+		} + 10;
+	}
+
+	public int switchExpr2() {
+		return switch (5) {
+		case 1, 2: 
+			System.out.println("Hello");
+		case 3: 
+			yield 10;
+		default: 
+			yield 20;
+		} + 10;
+	}
+
+	public void arrowSwitch() {
+		switch (5) {
+			case 1, 2 -> System.out.println("Hello");
+			case 3 -> {
+				System.out.println("");
+				break;
+			}
+		}
+	}
+
+	public void emptySwitch() {
+		switch (5) {
+		}
+	}
+}