FIC: Make SAM conversions also for fun interfaces, add base test

compiler/testData/diagnostics/tests/funInterface/basicFunInterfaceConversion.kt

@@ -0,0 +1,12 @@
+// !LANGUAGE: +NewInference +FunctionInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun interface Foo {
+    fun invoke()
+}
+
+fun foo(f: Foo) {}
+
+fun test() {
+    foo {}
+}