[Experiment] [BROKEN] Make stored captures trivial

[milseman]

_StoredCapture stored an Any?, which is rarely set to anything non-nil, but since it could it is non-trivial. This experiment tries to see the perf overhead of this non-triviality.

[milseman]

This gives us a somewhat robust (given our benchmark suite's variability) perf improvement of a few percent typically. In its current state, this code breaks support for value captures and that would need to be fixed by setting the valueIndex to the index in an array of capture-values maintained by the processor.

=== Regressions ======================================================================
- CompilerMessages_All                    104ms	102ms	1.3ms		1.3%
- CompilerMessages_All_Scalar             86.7ms	85.6ms	1.01ms		1.2%
- EmailLookaheadNoMatches_All             41.8ms	41.3ms	434µs		1.1%
- SubtractionCCC_All_Scalar               21.9ms	21.5ms	388µs		1.8%
- IntersectionCCC_All                     22.5ms	22.2ms	363µs		1.6%
- AnchoredNotFound_Whole                  9.08ms	8.92ms	154µs		1.7%
- AnchoredNotFound_Whole_Scalar           5.81ms	5.67ms	143µs		2.5%
- EmailLookahead_All_Scalar               22.8ms	22.7ms	99.9µs		0.4%
- EagarQuantWithTerminal_Whole_Scalar     1.42ms	1.36ms	58.7µs		4.3%
=== Improvements =====================================================================
- EmailRFCNoMatches_All                   136ms	139ms	-3.34ms		-2.4%
- symDiffCCC_All                          48.4ms	50ms	-1.63ms		-3.3%
- EmojiRegex_All                          71.6ms	73.2ms	-1.6ms		-2.2%
- EmojiRegex_All_Scalar                   48.4ms	50ms	-1.59ms		-3.2%
- symDiffCCC_All_Scalar                   48.5ms	50ms	-1.51ms		-3.0%
- DiceRollsInText_All_Scalar              43.6ms	44.7ms	-1.09ms		-2.4%
- Words_All_Scalar                        12.5ms	13.6ms	-1.02ms		-7.5%
- InvertedCCC_All                         19.7ms	20.7ms	-996µs		-4.8%
- ReluctantQuant_Whole_Scalar             9.77ms	10.7ms	-955µs		-8.9%
- ReluctantQuant_Whole                    9.89ms	10.8ms	-937µs		-8.7%
- Words_All                               13.2ms	14.1ms	-935µs		-6.6%
- IntersectionCCC_All_Scalar              21.7ms	22.4ms	-669µs		-3.0%
- DiceRollsInText_All                     46.5ms	47.2ms	-668µs		-1.4%
- InvertedCCC_All_Scalar                  19.8ms	20.4ms	-668µs		-3.3%
- EmailRFC_All                            63.7ms	64.3ms	-631µs		-1.0%
- EmailBuiltinCharacterClass_All_Scalar   12.5ms	13.1ms	-600µs		-4.6%
- NotFound_All_Scalar                     6.3ms	6.76ms	-460µs		-6.8%
- NotFound_All                            7.02ms	7.47ms	-448µs		-6.0%
- Css_All                                 3.36ms	3.79ms	-434µs		-11.4%
- BasicBuiltinCharacterClass_All_Scalar   7.34ms	7.75ms	-415µs		-5.4%
- BasicBuiltinCharacterClass_All          8.06ms	8.45ms	-384µs		-4.5%
- Css_All_Scalar                          2.88ms	3.26ms	-380µs		-11.6%
- BasicRangeCCC_All                       10.8ms	11.2ms	-345µs		-3.1%
- LiteralSearchNotFound_All_Scalar        5.68ms	6ms	-326µs		-5.4%
- BasicCCC_All_Scalar                     10.4ms	10.7ms	-313µs		-2.9%
- Numbers_All_Scalar                      6.42ms	6.73ms	-308µs		-4.6%
- CaseInsensitiveCCC_All                  11.6ms	11.9ms	-304µs		-2.6%
- LiteralSearchNotFound_All               6.47ms	6.77ms	-302µs		-4.5%
- LiteralSearch_All                       6.69ms	6.98ms	-295µs		-4.2%
- BasicCCC_All                            10.4ms	10.7ms	-287µs		-2.7%
- HangulSyllable_All                      6.89ms	7.17ms	-285µs		-4.0%
- GraphemeBreakNoCap_All                  4.09ms	4.37ms	-280µs		-6.4%
- BasicRangeCCC_All_Scalar                10.8ms	11.1ms	-279µs		-2.5%
- CaseInsensitiveCCC_All_Scalar           11.5ms	11.8ms	-278µs		-2.4%
- SubtractionCCC_All                      21.4ms	21.6ms	-274µs		-1.3%
- EmailLookaheadNoMatches_All_Scalar      27.8ms	28.1ms	-267µs		-0.9%
- GraphemeBreakNoCap_All_Scalar           3.52ms	3.76ms	-243µs		-6.5%
- LiteralSearch_All_Scalar                5.96ms	6.2ms	-237µs		-3.8%
- HangulSyllable_All_Scalar               6.16ms	6.39ms	-232µs		-3.6%
- MACAddress                              2.77ms	2.98ms	-216µs		-7.2%
- MACAddress_Scalar                       2.35ms	2.54ms	-187µs		-7.4%
- IPv6Address                             3.85ms	3.99ms	-145µs		-3.6%
- EmailBuiltinCharacterClass_All          12.7ms	12.8ms	-132µs		-1.0%
- HangulSyllable_First_Scalar             2.94ms	3.07ms	-130µs		-4.2%
- IPv4Address                             2.4ms	2.51ms	-117µs		-4.7%
- HangulSyllable_First                    3.3ms	3.4ms	-97.5µs		-2.9%
- DiceNotation_Scalar                     4.59ms	4.69ms	-94.1µs		-2.0%
- DiceNotation                            4.93ms	5.01ms	-82.4µs		-1.6%
- IPv6Address_Scalar                      2.77ms	2.85ms	-77.2µs		-2.7%
- Lines_All                               1.76ms	1.84ms	-76.8µs		-4.2%
- Lines_All_Scalar                        1.71ms	1.78ms	-76µs		-4.3%
- IPv4Address_Scalar                      2.19ms	2.25ms	-61.8µs		-2.8%
- EmailLookaheadList_Scalar               5.15ms	5.21ms	-58.1µs		-1.1%
- ReluctantQuantWithTerminal_Whole_Scalar 6.63ms	6.68ms	-49.3µs		-0.7%

Beyond this, we could also improve the struct's layout, but that's a much lower-impact change for further down the line.