Allow "create actual" for function even if partially-compatible exists

So #KT-20163 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/createImpl/CreateActualFix.kt

@@ -137,7 +137,8 @@ sealed class CreateActualFix<out D : KtNamedDeclaration>(
             val d = DiagnosticFactory.cast(diagnostic, Errors.NO_ACTUAL_FOR_EXPECT)
             val declaration = d.psiElement as? KtNamedDeclaration ?: return null
             val compatibility = d.c
-            if (compatibility.isNotEmpty()) return null
+            // For function we allow it, because overloads are possible
+            if (compatibility.isNotEmpty() && declaration !is KtFunction) return null
             val actualPlatform = d.b.getMultiTargetPlatform() as? MultiTargetPlatform.Specific ?: return null
             return when (declaration) {
                 is KtClassOrObject -> CreateActualClassFix(declaration, actualPlatform)

idea/testData/multiModuleQuickFix/overload/header/header.kt

@@ -0,0 +1,5 @@
+// "Create actual function for platform JVM" "true"
+
+expect fun <caret>foo(arg: Int): String
+
+expect fun foo(arg: String): String

idea/testData/multiModuleQuickFix/overload/header/header.kt.after

@@ -0,0 +1,5 @@
+// "Create actual function for platform JVM" "true"
+
+expect fun foo(arg: Int): String
+
+expect fun foo(arg: String): String

idea/testData/multiModuleQuickFix/overload/jvm/foo.kt

@@ -0,0 +1,3 @@
+// foo: to be implemented
+
+actual fun foo(arg: String) = arg

idea/testData/multiModuleQuickFix/overload/jvm/foo.kt.after

@@ -0,0 +1,7 @@
+// foo: to be implemented
+
+actual fun foo(arg: String) = arg
+
+actual fun foo(arg: Int): String {
+    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+}