Byte threshold

[milseman]

Built on top of OS version availability PR: swiftlang#641

Get a recent enough toolchain (I'm using 2023-03-06) and build using:

xcrun --toolchain swift swift build -c release 

Build and run benchmark suite prior to 1ea82e6:

.build/release/RegexBenchmark --samples 20 --save main_unmodified

Run again, comparing results:

.build/release/RegexBenchmark --samples 20 --compare main_unmodified

Results:

Comparing against saved benchmark result main_unmodified
=== Regressions ======================================================================
- CompilerMessagesAll                     129ms	118ms	11.1ms		9.4%
- EmailRFCNoMatchesAll                    142ms	133ms	9.01ms		6.8%
- EmojiRegexAll                           80.1ms	71.1ms	8.99ms		12.6%
- EmailRFCAll                             68.4ms	61.2ms	7.15ms		11.7%
- DiceRollsInTextAll                      71.7ms	66ms	5.75ms		8.7%
- EmailLookaheadNoMatchesAll              45.1ms	40.8ms	4.31ms		10.6%
- EmailBuiltinCharacterClassAll           28.5ms	26ms	2.45ms		9.4%
- EmailLookaheadAll                       41.5ms	39.2ms	2.22ms		5.7%
- symDiffCCC                              50ms	47.8ms	2.14ms		4.5%
- SubtractionCCC                          23ms	21ms	2.02ms		9.6%
- IntersectionCCC                         23.5ms	21.5ms	1.97ms		9.2%
- ReluctantQuantWhole                     15.8ms	13.8ms	1.96ms		14.1%
- ReluctantQuantWithTerminalWhole         10.5ms	8.99ms	1.53ms		17.0%
- LiteralSearchAll                        7.37ms	6.42ms	951µs		14.8%
- BasicCCC                                11.4ms	10.5ms	901µs		8.6%
- LiteralSearchNotFoundAll                7.11ms	6.25ms	866µs		13.9%
- BasicRangeCCC                           11.7ms	10.8ms	849µs		7.8%
- CaseInsensitiveCCC                      12.5ms	11.6ms	844µs		7.3%
- NotFoundAll                             7.76ms	6.93ms	832µs		12.0%
- AnchoredNotFoundWhole                   9.56ms	8.83ms	726µs		8.2%
- HangulSyllableAll                       7.36ms	6.66ms	698µs		10.5%
- CssAll                                  4.62ms	3.94ms	684µs		17.4%
- BasicBuiltinCharacterClassAll           16.5ms	15.9ms	673µs		4.2%
- InvertedCCC                             21.4ms	20.7ms	654µs		3.2%
- NumbersAll                              13ms	12.6ms	445µs		3.5%
- HangulSyllableFirst                     3.6ms	3.18ms	418µs		13.1%
- DiceNotation                            7.45ms	7.08ms	374µs		5.3%
- WordsAll                                23ms	22.6ms	348µs		1.5%
- EmailLookaheadList                      9.98ms	9.69ms	286µs		3.0%
- GraphemeBreakNoCapAll                   7.2ms	6.95ms	247µs		3.5%
- IPv4Address                             3.08ms	2.83ms	244µs		8.6%
- IPv6Address                             4.15ms	4.02ms	124µs		3.1%
- MACAddress                              3.09ms	2.98ms	103µs		3.5%
- LinesAll                                3.15ms	3.07ms	81.5µs		2.7%
- EagarQuantWithTerminalWhole             2.64ms	2.58ms	58.4µs		2.3%

(If the benchmark suite fatal errors out, that usually means the device was too variant. You can run it again. I'm going to probably increase the tolerance of this a little in the future).