check-style: Don't turn off formatting when the chunk starts on line 1

Before this, new files introduced by the range of commits checked were
not considered for formatting b/c uncrustify was always turned off in
the beginning of the files, and never turned back on.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2733>

check-style.py

@@ -42,6 +42,7 @@ def reformat_chunks(chunks, rewrite):
     def create_temp_file(file, start, end):
         with open(file) as f:
             tmp = tempfile.NamedTemporaryFile()
+            if start > 1:
                 tmp.write(b'/** *INDENT-OFF* **/\n')
             for i, line in enumerate(f, start=1):
                 if i == start - 1: