[PRISM] Enable more passing tests

test/.excludes-prism/TestRubyLiteral.rb

@@ -1,3 +1,2 @@
 exclude(:test_dregexp, "https://github.com/ruby/prism/issues/2664")
-exclude(:test_hash_value_omission, "unknown")
 exclude(:test_string, "https://github.com/ruby/prism/issues/2331")

test/.excludes-prism/TestSyntax.rb

@@ -1,16 +1,12 @@
 exclude(:test__END___cr, "unknown")
 exclude(:test_argument_forwarding_with_super, "unknown")
 exclude(:test_argument_forwarding, "unknown")
-exclude(:test_dedented_heredoc_concatenation, "unknown")
 exclude(:test_dedented_heredoc_continued_line, "unknown")
 exclude(:test_duplicated_when, "unknown")
 exclude(:test_error_message_encoding, "unknown")
-exclude(:test_heredoc_cr, "unknown")
-exclude(:test_heredoc_no_terminator, "unknown")
 exclude(:test_it, "https://github.com/ruby/prism/issues/2323")
 exclude(:test_keyword_invalid_name, "unknown")
 exclude(:test_keyword_self_reference, "unknown")
-exclude(:test_methoddef_endless_command, "unknown")
 exclude(:test_numbered_parameter, "unknown")
 exclude(:test_optional_self_reference, "unknown")
 exclude(:test_syntax_error_at_newline, "unknown")