Isolines v1.2.0 runs out of memory

[jake-dnd]

I am using the 1.2.0 version of your library as it is embedded in the turf isolines feature.

However I am running out of memory and crashing on some of my data sets. Investigating it showed that we were having hundreds of thousands of points in the p array in tracePath() even in relatively modest sized grids.

I tested upgrading (even to 1.2.3) but this gives different results that are incorrect for my use case.

My hacky solution is to break out of the while loop if the p.length becomes illogically large (100,000+).

Given the age of 1.2.0 and the rewrite of that area of code, I cannot do a PR for my modification.
Forgive me if reporting this as a defect is incorrect, but I wanted to stay on the right side of the license.

Thank you for your library :)