Enable DSL FP tests.

These new tests rely on compiled shaders that live in the
`tests/sksl/dslfp/` directory; this CL updates the Bazel and
emscripten build scripts to include these shaders.

Change-Id: Ib670682af8bf451a4473504dd4cc76a0e9222129
Bug: skia:11854
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/400097
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
4 files changed