FIR: Refactor nested scope, fix super-type resolving jump context

#KT-24017 Fixed

compiler/testData/fir/resolve/multifile/NestedSuperType.1.kt

@@ -0,0 +1,7 @@
+package b
+
+import c.C
+
+open class B : C() {
+    open class NestedInB : NestedInC()
+}

compiler/testData/fir/resolve/multifile/NestedSuperType.2.kt

@@ -0,0 +1,5 @@
+package c
+
+open class C {
+    open class NestedInC
+}

compiler/testData/fir/resolve/multifile/NestedSuperType.kt

@@ -0,0 +1,8 @@
+package a
+
+import b.B
+
+class A : B() {
+    class NestedInA1 : NestedInB()
+    class NestedInA2 : NestedInC()
+}

compiler/testData/fir/resolve/multifile/NestedSuperType.txt

@@ -0,0 +1,9 @@
+FILE: NestedSuperType.kt
+    unknown final class A() : R/b.B/ {
+        unknown final class NestedInA1() : R/b.B.NestedInB/ {
+        }
+
+        unknown final class NestedInA2() : R/c.C.NestedInC/ {
+        }
+
+    }