in to_string(): removed initial comment (besides having several typos, it was incosistent: other test functions don't explain what the tested function does); avoided all-uppercase identifiers and shortened test expression; minor cleanup

[SVN r34111]

libs/dynamic_bitset

@@ -1 +1 @@
-Subproject commit 896a792becc0db1517547e1c4c88bb68540e3f63
+Subproject commit fb5e1d024d1a5924949965028650ad150f3ea1dc