[canvaskit] Add job to compile GMTests js/wasm

Next step is to add the following task:
Test-Ubuntu18-EMCC-Golo-GPU-QuadroP400-wasm-Release-All-WasmGMTests_WebGL2

Bug: skia:10812
Change-Id: Ibe45b7205cebd30f0e7904ea6d93a01ea3df87fe
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/324617
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
7 files changed