Revert "Formatter: Escape non-printable characters in literals"

[straight-shoota]

Reverts #11520

This change broke the format of grapheme_spec which was merged in #11472 in the mean time: https://github.com/crystal-lang/crystal/runs/4554342641?check_suite_focus=true

grapheme_spec has string literals with graphemes containing non-printable characters. The formatter produces this diff (I isolated and reorderd the lines for better readability):

-    it_iterates_graphemes "ܐ܏ܒܓܕ ", ['\u0710', "\u070F\u0712", '\u0713', '\u0715']
+    it_iterates_graphemes "ܐ\u070Fܒܓܕ", ['\u0710', "\u070F\u0712", '\u0713', '\u0715']

-    it_iterates_graphemes "*👩‍❤️‍💋‍👩*", ['*', "\u{1F469}\u200D\u2764\uFE0F\u200D\u{1F48B}\u200D\u{1F469}", '*']
+    it_iterates_graphemes "*👩\u200D❤️\u200D💋\u200D👩*", ['*', "\u{1F469}\u200D\u2764\uFE0F\u200D\u{1F48B}\u200D\u{1F469}", '*']

-    it_iterates_graphemes "👩‍❤️‍💋‍👩", ["\u{1F469}\u200D\u2764\uFE0F\u200D\u{1F48B}\u200D\u{1F469}"]
+    it_iterates_graphemes "👩\u200D❤️\u200D💋\u200D👩", ["\u{1F469}\u200D\u2764\uFE0F\u200D\u{1F48B}\u200D\u{1F469}"]

-    it_iterates_graphemes "🏋🏽‍♀️", ["\u{1F3CB}\u{1F3FD}\u200D\u2640\uFE0F"]
+    it_iterates_graphemes "🏋🏽\u200D♀️", ["\u{1F3CB}\u{1F3FD}\u200D\u2640\uFE0F"]

-    it_iterates_graphemes "🏳️‍🌈", ["\u{1F3F3}\uFE0F\u200D\u{1F308}"]
+    it_iterates_graphemes "🏳️\u200D🌈", ["\u{1F3F3}\uFE0F\u200D\u{1F308}"]

I think that's a legitimate use case for non-printable characters in string literals. Thus we should revert #11520.
We can reconsider whether we want to improve this feature and add it again or drop it.