Be a bit stricter when comparing parser translator tokens

When there were more actual tokens than expected tokens, the test would still pass.

Now it's possible to receive an assertion like this:
```
expected: []
actual: [:tNL, [nil, #<Parser::Source::Range comment_single.txt 8...9>]]
<[]> expected but was
<[:tNL, [nil, #<Parser::Source::Range comment_single.txt 8...9>]]>
```

Author: Earlopain

test/prism/ruby/parser_test.rb

@@ -207,15 +207,14 @@ def assert_equal_asts_message(expected_ast, actual_ast)
 
     def assert_equal_tokens(expected_tokens, actual_tokens)
       if expected_tokens != actual_tokens
-        expected_index = 0
-        actual_index = 0
+        index = 0
+        max_index = [expected_tokens, actual_tokens].map(&:size).max
 
-        while expected_index < expected_tokens.length
-          expected_token = expected_tokens[expected_index]
-          actual_token = actual_tokens.fetch(actual_index, [])
+        while index <= max_index
+          expected_token = expected_tokens.fetch(index, [])
+          actual_token = actual_tokens.fetch(index, [])
 
-          expected_index += 1
-          actual_index += 1
+          index += 1
 
           # There are a lot of tokens that have very specific meaning according
           # to the context of the parser. We don't expose that information in