Lambda --> reference: correct handling of parameter-less function

Issue #KT-15556 Fixed

idea/testData/intentions/convertLambdaToReference/defaultConstructor.kt

@@ -0,0 +1,5 @@
+class Foo
+fun usage(f: () -> Foo) {}
+fun test() {
+    usage {<caret> Foo() }
+}

idea/testData/intentions/convertLambdaToReference/defaultConstructor.kt.after

@@ -0,0 +1,5 @@
+class Foo
+fun usage(f: () -> Foo) {}
+fun test() {
+    usage(::Foo)
+}

idea/testData/intentions/convertLambdaToReference/nestedLambdaWithReceiver.kt

@@ -1,4 +1,4 @@
-// IS_APPLICABLE: false
+// IS_APPLICABLE: true
 // WITH_RUNTIME
 
 fun foo() {

idea/testData/intentions/convertLambdaToReference/nestedLambdaWithReceiver.kt.after

@@ -0,0 +1,9 @@
+// IS_APPLICABLE: true
+// WITH_RUNTIME
+
+fun foo() {
+    listOf(1).forEach { run(it::bar) }
+}
+
+fun Int.bar() {
+}