Bump integration test timeout as well

not very happy about this but it's better than having a flaky CI...

CMakeLists.txt

@@ -347,7 +347,7 @@ if(${CMAKE_BUILD_TYPE} STREQUAL "Release")
   add_pyston_test(max_compilation_tier tests -a=-O -a=-X -t50)
 endif()
 add_pyston_test(defaults cpython --exit-code-only --skip-failing -t100)
-add_pyston_test(defaults integration --exit-code-only --skip-failing -t600)
+add_pyston_test(defaults integration --exit-code-only --skip-failing -t900)
 if(ENABLE_EXTRA_TESTS)
   add_pyston_test(defaults extra -t900 --exit-code-only)
 endif()