Implement "move expression up/down" action handler

idea/testData/codeInsight/moveUpDown/closingBraces/when/when1.kt

@@ -0,0 +1,17 @@
+// IS_APPLICABLE: false
+// MOVE: down
+
+fun foo(n: Int) {
+    when (n) {
+        0 -> {
+
+        }
+        1 -> {
+
+        }
+        else -> {
+
+        }
+    }<caret>
+    val x = ""
+}