[FIR] Fix Substitution scope key to avoid accidental matches

compiler/testData/ir/irText/firProblems/DelegationAndInheritanceFromJava.kt

@@ -0,0 +1,18 @@
+// FILE: Foo.java
+
+import java.util.Set;
+
+public class Foo {
+    public interface A extends Set<String> {}
+
+    public interface B extends Set<String> {}
+}
+
+// FILE: DelegationAndInheritanceFromJava.kt
+
+import Foo.*
+import java.util.HashSet
+
+class Impl(b: B): A, B by b
+
+fun box() = "OK"