Implement "move class-level declaration up/down" action handler

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor1.kt

@@ -0,0 +1,6 @@
+// MOVE: down
+// IS_APPLICABLE: false
+val x: String
+    <caret>get() {
+        return ""
+    }

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor2.kt

@@ -0,0 +1,6 @@
+// MOVE: up
+// IS_APPLICABLE: false
+val x: String
+    <caret>get() {
+        return ""
+    }

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor3.kt

@@ -0,0 +1,8 @@
+// MOVE: down
+var x: String
+    <caret>get() {
+        return ""
+    }
+    set(v: String) {
+        // test
+    }

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor3.kt.after

@@ -0,0 +1,8 @@
+// MOVE: down
+var x: String
+    set(v: String) {
+        // test
+    }
+    <caret>get() {
+        return ""
+    }

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor4.kt

@@ -0,0 +1,8 @@
+// MOVE: up
+var x: String
+    get() {
+        return ""
+    }
+    <caret>set(v: String) {
+        // test
+    }

idea/testData/codeInsight/moveUpDown/classBodyDeclarations/accessors/accessor4.kt.after

@@ -0,0 +1,8 @@
+// MOVE: up
+var x: String
+    <caret>set(v: String) {
+        // test
+    }
+    get() {
+        return ""
+    }