KT-64832 [FIR] Add more testData for invoke on local variables

Covers:
- suspend functional local variables
- overloads
- custom types with invoke operator

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeWithExtensionReceiver.kt

@@ -0,0 +1,9 @@
+fun foo() {
+    val ext: String.(Int) -> Unit
+
+    val usedReceiver = "foo"
+
+    val <!UNUSED_VARIABLE!>unusedReceiver<!> = "bar"
+
+    usedReceiver.ext(10)
+}