Import insertion algorithm

idea/testData/addImport/DropExplicitImports.kt.after

@@ -0,0 +1,14 @@
+// IMPORT: java.util.HashMap
+package p
+
+import java.sql.*
+import java.util.HashSet as JavaHashSet // alias import should not be dropped
+import java.util.concurrent // import of package should not be dropped because packages are not imported by *
+import java.util.*
+import java.util.Date
+
+fun foo() {
+    val v1 = JavaHashSet()
+    val v2 = Date()
+    val v3 = ArrayList()
+}