New J2K: separate nullability inference from common one & nullability bug fixes

It will be needed for structure mutability inference

#KT-21467 fixed
#KT-32609 fixed
#KT-32572 fixed
#KT-24677 fixed

nj2k/testData/newJ2k/issues/kt-32609.java

@@ -0,0 +1,8 @@
+import org.jetbrains.annotations.NotNull;
+
+public class Book implements Comparable<Book> {
+    @Override
+    public int compareTo(@NotNull Book o) {
+        return 0;
+    }
+}