[FIR2IR] Unwrap call-site substitution overrides

Generating IR declarations for use-site substitution overrides leads
to IR that is different from K1 as well as problems in signature
generation which relies on mangling. Use-site substitutions can contain
references to type parameters from the call-site which aren't handled
in mangling.

#KT-57022 Fixed

compiler/testData/ir/irText/firProblems/SignatureComputationComplexJavaGeneric.kt.txt

@@ -1,6 +1,6 @@
-class Test<T : Any?> : J<T> {
+class Inv<T : Any?> {
   constructor(x: T) /* primary */ {
-    super/*J*/<T>()
+    super/*Any*/()
     /* <init>() */
 
   }
@@ -9,8 +9,38 @@ class Test<T : Any?> : J<T> {
     field = x
     get
 
-  fun test(b: B<T>) {
+}
+
+class Test_1<TT : Any?> : JavaClass1<TT> {
+  constructor(x: TT) /* primary */ {
+    super/*JavaClass1*/<TT>()
+    /* <init>() */
+
+  }
+
+  val x: TT
+    field = x
+    get
+
+  fun test(b: B<TT>) {
     b.output(x = <this>.<get-x>())
   }
 
 }
+
+class Test_2<TT : Any?> : JavaClass2<TT, Inv<TT>> {
+  constructor() /* primary */ {
+    super/*JavaClass2*/<TT, Inv<TT>>()
+    /* <init>() */
+
+  }
+
+  fun process(b: B<TT, Inv<TT>>) {
+    b.output(output = Inv<TT>(x = b.element()))
+  }
+
+}
+
+fun <R : Any?> test_3(jb: B<R>, r: R) {
+  jb.output(x = r)
+}