Optimize Imports tests: Switch to generated approach

Move test and rename test data
Delete unused testdata
Rewrite OptimizeImportOnFlyTest

idea/testData/editor/optimizeImports/Kt2488EnumEntry/Kt2488EnumEntry.after.kt

@@ -0,0 +1,12 @@
+package test
+
+import test.MyEnum.ONE
+
+fun main(args: Array<String>) {
+    println(ONE)
+}
+
+public enum class MyEnum {
+    ONE
+    TWO
+}

idea/testData/editor/optimizeImports/Kt2488EnumEntry/Kt2488EnumEntry.kt

@@ -0,0 +1,12 @@
+package test
+
+import test.MyEnum.ONE
+
+fun main(args: Array<String>) {
+    println(ONE)
+}
+
+public enum class MyEnum {
+    ONE
+    TWO
+}