Symbol#inspect is quoted on TruffleRuby for non-ASCII identifiers

[eregon]

From ruby/prism#2264 (comment)

$ ruby -e 'p :🌊'
CRuby
:🌊
TruffleRuby
:"🌊"

Once fixed we should be able to remove these excludes: https://github.com/ruby/prism/pull/2264/files#diff-160859519e6d8d817511d99ddad0f95f7d1be541ab25a6d4877ef3c7d8f8ee41