Fixed a bug in import insertion algorithm

idea/testData/addImport/ConflictingNameAppearsAndHasUsage6.dependency.kt

@@ -0,0 +1,3 @@
+package dependency
+
+fun String.Date(p: Int) {}

idea/testData/addImport/ConflictingNameAppearsAndHasUsage6.kt

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+// IMPORT: java.util.ArrayList
+package p
+
+import java.sql.*
+import dependency.Date // import of function does not affect class name conflict
+
+val d = Date(1)

idea/testData/addImport/ConflictingNameAppearsAndHasUsage6.kt.after

@@ -0,0 +1,9 @@
+// IMPORT: java.util.ArrayList
+package p
+
+import java.sql.*
+import dependency.Date // import of function does not affect class name conflict
+import java.util.*
+import java.sql.Date
+
+val d = Date(1)