K2: add test for KT-56520, case (4), callable references (unbound)

Again, both frontends here ignored classifiers from
explicit star imported scope (some.HashMap, java.util.HashMap)
because of their ambiguity. In case of K2, it works so due to logic
in BodyResolveComponents.resolveRootPartOfQualifier.
This function is called to resolve qualifier without receiver.
See also cases (3) and (7).

compiler/testData/diagnostics/testsWithStdLib/resolve/ambiguousTypeReferences/callableReferenceUnboundCase.fir.txt

@@ -0,0 +1,4 @@
+FILE: test.kt
+    public final fun test(): R|kotlin/reflect/KProperty1<kotlin/collections/HashMap<kotlin/String, kotlin/String>, kotlin/Int>| {
+        ^test Q|kotlin/collections/HashMap|::R|SubstitutionOverride<java/util/HashMap.size: R|kotlin/Int|>|
+    }

compiler/testData/diagnostics/testsWithStdLib/resolve/ambiguousTypeReferences/callableReferenceUnboundCase.kt

@@ -0,0 +1,20 @@
+// FIR_IDENTICAL
+// ISSUE: KT-56520 (case 4, unbound)
+// FIR_DUMP
+// FULL_JDK
+
+// FILE: some/HashMap.java
+
+package some;
+
+public class HashMap<K, V> extends java.util.HashMap<K, V> {}
+
+// FILE: test.kt
+
+import java.util.*
+import some.*
+
+fun test() =
+    // Ok in both K1 & K2.
+    // K1 & K2 resolve this to kotlin.collections.HashMap.
+    HashMap<String, String>::size