Error with fill/colorMode combo

`colorMode(HSB, 360);
fill(-1, -1, -1);`

gets:
"Cannot read property '0' of undefined"

Maybe we can have PJS throw a nicer error than that or not have an error, depending on what the issue is with that code (haven't investigated yet).

Reproduce the colorMode(HSB, 360) and fill(-1, -1, -1) snippet in the live editor, then trace how these calls are handled. The issue names no files or tests, so first locate the relevant colorMode and fill entry points. Done means either preventing the failure or replacing it with a clear, intentional error.

Written by the indexing model from the issue text.