[FIR] Add checking receivers of callable references

compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/genericInReceiver.kt

@@ -0,0 +1,7 @@
+fun test_1(a: String, s: String) {
+    val pair = s.let(a::to)
+}
+
+fun test_2(a: String, s: String) {
+    val pair = s.let { a.to(it) }
+}