[3.14] gh-134582: Fix t-strings untokenize() roundtrip removing space between braces (GH-134603) (#134659)

gh-134582: Fix t-strings untokenize() roundtrip removing space between braces (GH-134603)
(cherry picked from commit 52509cc94b1a18cb325dbfa7e5f830b32759a903)

Co-authored-by: Loïc Simon <loic.pano@gmail.com>