KT-1755 Duplicates in completion

#KT-1755 fixed

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

@@ -0,0 +1,5 @@
+package classimporttest
+
+fun test() {
+    TTTes<caret>
+}

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

@@ -0,0 +1,3 @@
+package forimport
+
+class TTTest {}

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

@@ -0,0 +1,7 @@
+package classimporttest
+
+import forimport.TTTest
+
+fun test() {
+    TTTest
+}