[java][switch completion] IDEA-270439 Code completion for pattern matching in switch

Adjust the completion variants for switch statements and expressions

GitOrigin-RevId: 05119897b0eb72bb875097cd197f376534d15db9

java/java-tests/testData/codeInsight/completion/normal/CompleteNullInSwitchExpr_after.java

@@ -0,0 +1,21 @@
+
+class Main {
+
+  int f(Object o) {
+    return switch(o) {
+      case Integer i, null<caret>
+    }
+  }
+
+  int g(Object o) {
+    return switch(o) {
+      case null<caret>, Integer i
+    }
+  }
+
+  int h(Object o) {
+    return switch(o) {
+      case null<caret>
+    }
+  }
+}