KT-1151 Code completion for not imported extension functions - test for completion extension function without params

idea/testData/completion/handlers/multifile/ExtensionFunctions-1.kt

@@ -0,0 +1,6 @@
+package first
+
+fun firstFun() {
+    val a = ""
+    a.hello<caret>
+}

idea/testData/completion/handlers/multifile/ExtensionFunctions-2.kt

@@ -0,0 +1,4 @@
+package second
+
+fun String.helloFun() {
+}

idea/testData/completion/handlers/multifile/ExtensionFunctions.kt.after

@@ -0,0 +1,8 @@
+package first
+
+import second.helloFun
+
+fun firstFun() {
+    val a = ""
+    a.helloFun()
+}