combine compiler and renderer tests?

[tdhock]

we may attempt to combine all non-CRAN tests (currently run in separate compiler and renderer CI jobs).

• CRAN would not start chromote, nor JS coverage.
• combined compiler/renderer job would start chromote, and compute R/JS coverage.

Related to #210

what do you think @suhaani-agarwal ?

[suhaani-agarwal]

That’s a great idea! I’ll try combining the compiler and renderer tests into a single job and compute both R and JS coverage together , since we’re now using chromote for both, it might just work smoothly.