Add cuda 8/9.1 centos 6 builds, test GPU wheel on CPU only container. (#3309)

* Add cuda 8/9.1 centos 6 builds, test GPU wheel on CPU only container.

* Add Google test

tests/ci_build/build_via_cmake.sh

@@ -1,7 +1,20 @@
 #!/usr/bin/env bash
+set -e
 
-make clean
+# Build gtest via cmake
+rm -rf gtest
+wget https://github.com/google/googletest/archive/release-1.7.0.zip
+unzip release-1.7.0.zip
+mv googletest-release-1.7.0 gtest && cd gtest
+cmake . && make 
+mkdir lib && mv libgtest.a lib
+cd ..
+rm -rf release-1.7.0.zip*
+
+rm -rf build
 mkdir build
 cd build
-cmake .. "$@"
-make
+cmake .. "$@" -DGOOGLE_TEST=ON -DGTEST_ROOT=../gtest
+make clean
+make -j
+cd ..