Remove Chromium unit tests from standalone solution.

Remove Chromium unit tests from standalone solution.

These tests rely on the SwiftShader libraries to be loaded from a swiftshader/
subdirectory. The PowerVR samples are a better smoke test for the standalone
build, so we can just remove the Chromium unit tests from the Visual Studio
solution.

Bug swiftshader:42

Change-Id: Ia7d73a62aac4a202750e630666143c920fec65b7
Reviewed-on: https://swiftshader-review.googlesource.com/9268
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>