builtin: Add CTLESC before all CCTLs in dollar single quote

If a backslash that comes from dollar-single quote escape sequence
is used as a pattern, it should be escaped automatically so that
it's interpreted as a literal backslash, rather than as a quoting
character.

Reported-by: Martijn Dekker <martijn@inlv.org>
Fixes: 776424a8f915 ("parser: Add dollar single quote")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>