KT-12669 Completion should show variant with () when there is default lambda

#KT-12669

idea/idea-completion/testData/handlers/basic/highOrderFunctions/OptionalParameters3.kt

@@ -0,0 +1,9 @@
+fun xfoo(p: () -> Unit = {}){}
+
+fun test() {
+    xfo<caret>
+}
+
+// ELEMENT: xfoo
+// TAIL_TEXT: " {...} (p: () -> Unit = ...) (<root>)"
+

idea/idea-completion/testData/handlers/basic/highOrderFunctions/OptionalParameters3.kt.after

@@ -0,0 +1,9 @@
+fun xfoo(p: () -> Unit = {}){}
+
+fun test() {
+    xfoo { <caret> }
+}
+
+// ELEMENT: xfoo
+// TAIL_TEXT: " {...} (p: () -> Unit = ...) (<root>)"
+