[ts] Replace Array constructors with dynamic initialization for packed number arrays

[koteelok]

In some places, you use new Array(size) to make number arrays. But JS fills the array with empty space and V8 will treat them as HOLEY_SMI_ELEMENTS and HOLEY_DOUBLE_ELEMENTS instead of PACKED_SMI_ELEMENTS and PACKED_DOUBLE_ELEMENTS.

I grepped through codebase and fixed this in some places, but I don’t think it will result in any noticeable speed-up. I just "scratched the itch"

Feel free to reject, if you don't care :P