Add IsNull expression to vortex-jni #7358

Performance Gate Passed

⚡ 2 improved benchmarks
✅ 1120 untouched benchmarks
⏩ 1530 skipped benchmarks¹

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	Simulation	`take_10k_contiguous`	314.9 µs	257 µs	+22.52%
⚡	Simulation	`take_10k_random`	251.2 µs	193.3 µs	+29.94%

_{Comparing rk/jniisnotnull (aa348a6) with develop (8974afe)}

1530 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩