skia2/tests/sksl/errors/SwitchDuplicateDefault.glsl

### Compilation failed:

error: 4: expected expression, but found 'default'
1 error
Add test for duplicate `default` switch-case. Surprisingly, this error is actually caught by our parser, which interprets the default label in a unique way. From the parser comments: "Requiring default: to be last (in defiance of C and GLSL) was a deliberate decision. Other parts of the compiler may rely upon this assumption." The comment is true--we don't check for duplicate default switch-case labels anywhere else in the code, just here in the parser. We rely on this, so we should have a test for it. Change-Id: I6df5c565aca4d4b8565b96638dce9504efc39ccc Bug: skia:11340 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/372617 Reviewed-by: Brian Osman <brianosman@google.com> Reviewed-by: Ethan Nicholas <ethannicholas@google.com> Commit-Queue: Brian Osman <brianosman@google.com> Commit-Queue: Ethan Nicholas <ethannicholas@google.com> Commit-Queue: John Stiles <johnstiles@google.com> Auto-Submit: John Stiles <johnstiles@google.com> 2021-02-19 20:13:46 +00:00			`### Compilation failed:`

			`error: 4: expected expression, but found 'default'`
			`1 error`