Fix SkSL test compilation on Windows.

The command-line length limit on Windows is very low (~8000 characters)
so it's infeasible to pass a large number of test files directly on the
command line. Fortunately, GN includes a built-in workaround.

Change-Id: I087fc00f11d81d84f677c2833406b4a6164ea6b3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/360716
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed