take into account containing class type params when accepting assignability (IDEA-71582)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/IDEA71582.java

@@ -0,0 +1,13 @@
+class Main {
+    static class C<T>
+    {
+        class D{}
+    }
+
+    void test()
+    {
+        C<String>.D o1 = null;
+        C<Object>.D o2 = null;
+        <error descr="Incompatible types. Found: 'Main.C<java.lang.Object>.D', required: 'Main.C<java.lang.String>.D'">o1 = o2</error>;
+    }
+}