Update Google Test to latest revision.
Update Google Test to latest revision.

Fixes (suppresses) Visual Studio 2017 warning (error) about std::tr1.

Change-Id: I3319dfa77d00e81e48ef7ef0ab884e131e9a039e
Reviewed-on: https://swiftshader-review.googlesource.com/15048
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader