Render tests erroring intermittently on Ubuntu

At a certain point (which varies from run to run), the render test suite errors out for me when running the tests with Node 8.11.3 on Ubuntu 16.04.

$ yarn run test-render
yarn run v1.16.0
$ node --max-old-space-size=2048 test/render.test.js
* skipped map-mode/tile-avoid-edges (skip - mapbox-gl-js does not need to render tiles)
* skipped map-mode/tile (skip - mapbox-gl-js does not need to render tiles)
* skipped regressions/mapbox-gl-js#3682 (skip - true)
.....
* passed background-color/colorSpace-hcl
* passed background-color/colorSpace-lab
* passed background-color/default
......
* passed text-offset/literal-multiline-anchorcenter-justifycenter-offsetnegative
* passed text-offset/literal-multiline-anchorcenter-justifycenter-offsetpositive
* passed text-offset/literal-multiline-anchorcenter-justifyleft-offsetnegative
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  149 ()
  Minor opcode of failed request:  4
  Value in failed request:  0x5c012b3
  Serial number of failed request:  9232
  Current serial number in output stream:  9234
error Command failed with exit code 1.

As mentioned, the test that triggers the error varies from run to run - in the example above it made it as far as text-offset, but I've also seen it throw as early as icon-opacity, image, & various other tests from run to run. The issue does not seem to be with any particular test itself, and if I run just a subset of tests (e.g. yarn run test-render text-offset), all tests pass and the suite does not throw an error.

cc @asheemmamoowala

Start with test/render.test.js and run yarn run test-render under Node 8.11.3 on Ubuntu 16.04, then compare the full suite with subsets such as text-offset. Investigate the intermittent X error reported in the test output; done means the complete render suite runs repeatedly without error in that environment.