parsing: support dot(s) in object keys

[kurkle]

Closes #10348
Closes #10501

@thabarbados sorry for stepping on your pr, but as I already put some time to it, I figured its less time spend for everyone if I post this.

This performs consistently a little bit better than master on the default parsing case (uPlot dataset):

pr:

50 runs done in 3389ms. Average: 67ms, min: 57ms, max: 127ms, variation: 70ms.

master:

50 runs done in 3602ms. Average: 72ms, min: 62ms, max: 135ms, variation: 73ms.

[thabarbados]

@kurkle No problem! It's great that you found a faster solution!

[thabarbados]

@kurkle, what do you think about adding performance tests? I think it would help new contributors. If you don't mind, I can try to realize it.

[kurkle]

@kurkle, what do you think about adding performance tests? I think it would help new contributors. If you don't mind, I can try to realize it.

That would be great!

[thabarbados]

@kurkle awesome! Can you share with me your large database and how you checked performance? I think this will be a good starting point.
If you don't mind, you can email it to thabarbados@gmail.com

[kurkle]

I've been usin uPlot bench dataset, available at https://github.com/leeoniya/uPlot/blob/master/bench/data.json

The data needs some pre-prosessing though. (See the chart.js bench at uPlot, that one is a good starting point)