Path parser crashes on small line distances on v5.22

[dnlbln]

Path parser has been rewritten in 5.22 and it causes a bug in a specific test case of our arrow charts. Click on the screenshot below to see the full resolution and you will have a good overview of the bug.

The offending code can be found on line 10 here: 63abce9

line 10, the code that crashes: path.match(commandPattern). I don't have complete insight in the vega codebase as this is my first time looking into it, but since .match can return null I am pretty confident that regardless the case that there should be a null check there.

I tested it myself and adding a null check will give the exact same result as in 5.21.

[jheer]

Thanks! Added null check for v5.22.1.