Add constraints between two different stub variables instead of creating constraint error due to T1 isn't subtype of T2

^KT-44241 Fixed

compiler/testData/codegen/box/inference/builderInference/kt44241.kt

@@ -0,0 +1,23 @@
+// !LANGUAGE: +UnrestrictedBuilderInference
+// WITH_RUNTIME
+
+import kotlin.experimental.ExperimentalTypeInference
+class A
+class B<K> {}
+class Scope<K11, K22>(
+    val key: K11,
+) {
+    fun emit(key: K22) {}
+}
+
+@OptIn(ExperimentalTypeInference::class)
+fun <K1, K2> B<K1>.scoped(@kotlin.BuilderInference binder: Scope<K1, K2>.() -> Unit) {}
+
+fun run(x: B<A>) {
+    x.scoped { emit(key) }
+}
+
+fun box(): String {
+    run(B<A>())
+    return "OK"
+}