Copy: Support top-level declarations

idea/testData/refactoring/copy/copyLocalVariable/after/bar/a.kt

@@ -0,0 +1,5 @@
+package bar
+
+fun a() {
+    val x = 1
+}

idea/testData/refactoring/copy/copyLocalVariable/after/foo/test.kt

@@ -0,0 +1,5 @@
+package foo
+
+fun a() {
+    val x = 1
+}

idea/testData/refactoring/copy/copyLocalVariable/before/foo/test.kt

@@ -0,0 +1,5 @@
+package foo
+
+fun a() {
+    val <caret>x = 1
+}

idea/testData/refactoring/copy/copyLocalVariable/copyLocalVariable.test

@@ -0,0 +1,4 @@
+{
+  "mainFile": "foo/test.kt",
+  "targetPackage": "bar"
+}