cbbf68b0da
Start the phasing out of TRE by disabling it by default. r317254 introduced a BSD_GREP_FASTMATCH knob (defaulting to on) for testing of bsdgrep with and without TRE enabled. More bugs have cropped up since then, and WITHOUT_BSD_GREP_FASTMATCH has shown in testing to be more stable than its counterpart. Approved by: emaste (mentor) Differential Revision: https://reviews.freebsd.org/D12381