KT-1103 Public outer function from different package and source file is not visible in completion:

- Stubs elements are enabled
- Changed method for selecting indexing policy for plugin and compiler
- Quick fix for import unresolved top-level function added

idea/testData/quickfix/autoImports/afterFunctionImport.kt

@@ -0,0 +1,8 @@
+// "Import Class" "true"
+package functionimporttest
+
+import functionimporttest.data.someTestFun
+
+fun functionImportTest() {
+    someTestFun()
+}

idea/testData/quickfix/autoImports/beforeFunctionImport.Data.Sample.kt

@@ -0,0 +1,7 @@
+package functionimporttest.data
+
+fun String.someTestFun() {
+}
+
+fun someTestFun() {
+}

idea/testData/quickfix/autoImports/beforeFunctionImport.Main.kt

@@ -0,0 +1,6 @@
+// "Import Class" "true"
+package functionimporttest
+
+fun functionImportTest() {
+    <caret>someTestFun()
+}