Move different_normalization_levels.erl as it now passes

Author: erszcz

test/known_problems/should_pass/different_normalization_levels.erl renamed to test/should_pass/different_normalization_levels.erl

@@ -5,13 +5,13 @@
 -type t() :: a | b | c.
 
 %% The problem is that the argument type stays the same (as top-level  normalization
-%% does not expand it) but the result type gets normalized to `a | b | c',
-%% and `t() | a' is not a subtype of `a | b | c' because it currently checks whether
-%% `t()' is a subtype of one of `a' or `b', or `c' (which it isn't).
+%% does not expand it) but the result type gets normalized to `a | b | c'.
+%% `t() | a' used not to be a subtype of `a | b | c' because it used to check whether
+%% `t()' was a subtype of one of `a' or `b', or `c' (which it wasn't).
 
 %% It surfaced because, for instance,
 %%    type() | any()
-%% is not a subtype of
+%% was not a subtype of
 %%    type()
 
 -spec f(t() | a) -> t().