Replace UpdatingVMFrame objects with parallel arrays

[NullVoxPopuli]

UpdatingVM pushes a frame for every block during revalidation, so the per-frame UpdatingVMFrame allocation is replaced with three parallel arrays for ops, handlers, and program counters. Behavior is unchanged.

[NullVoxPopuli]

Benchmark: main (bdb2580) vs nvp/perf/updating-vm-frames (8f236a5)

Ran via pnpm bench (the krausest js-framework-benchmark scenario in smoke-tests/benchmark-app, tracerbench, 20 samples each, 8x CPU throttle). Negative delta means the PR is faster. Only rows tracerbench marks significant (p < 0.05) are meaningful.

Phase	main median	PR median	Δ (estimator)	95% CI	Significant
Total duration	10,312ms	10,299ms	-24ms (-0.2%)	-298ms .. 206ms
render	157ms	158ms	1ms (+0.6%)	-7ms .. 6ms
render1000Items1	370ms	368ms	-1ms (-0.4%)	-9ms .. 11ms
clearItems1	40ms	40ms	-1ms (-2.0%)	-2ms .. 1ms
render1000Items2	312ms	314ms	-2ms (-0.6%)	-18ms .. 7ms
clearItems2	138ms	138ms	0ms (+0.1%)	-2ms .. 3ms
render10000Items1	2,918ms	2,918ms	2ms (+0.1%)	-94ms .. 88ms
clearManyItems1	383ms	384ms	-1ms (-0.1%)	-7ms .. 5ms
render10000Items2	2,915ms	2,909ms	-12ms (-0.4%)	-90ms .. 40ms
clearManyItems2	274ms	278ms	4ms (+1.4%)	-3ms .. 10ms
render1000Items3	286ms	287ms	1ms (+0.2%)	-18ms .. 14ms
append1000Items1	405ms	383ms	-7ms (-1.7%)	-43ms .. 18ms
append1000Items2	365ms	358ms	0ms (+0.0%)	-34ms .. 33ms
updateEvery10thItem1	320ms	315ms	-5ms (-1.4%)	-17ms .. 12ms
updateEvery10thItem2	357ms	357ms	-1ms (-0.2%)	-32ms .. 28ms
selectFirstRow1	87ms	83ms	-2ms (-2.2%)	-11ms .. 7ms
selectSecondRow1	69ms	66ms	-2ms (-2.5%)	-8ms .. 3ms
removeFirstRow1	221ms	210ms	-7ms (-3.4%)	-22ms .. 4ms
removeSecondRow1	213ms	203ms	-9ms (-4.4%)	-26ms .. 1ms
swapRows1	150ms	147ms	-4ms (-2.7%)	-19ms .. 7ms
swapRows2	149ms	137ms	-9ms (-5.8%)	-24ms .. 4ms
clearItems4	109ms	109ms	-1ms (-1.2%)	-4ms .. 1ms
paint	13ms	9ms	-2ms (-16.0%)	-6ms .. 0ms