Don't install test resources

Rather copy them to the binary dir. This avoids installing the
resources, which is affected by the DESTDIR variable.

The file(COPY) operation happens at configure-time rather than
install-time, which means that installation is no longer required to run
the tests.

rcl/test/CMakeLists.txt

@@ -309,5 +309,5 @@ rcl_add_custom_gtest(test_security_directory
 )
 
 # Install test resources
-install(DIRECTORY ${test_resources_dir_name}
-        DESTINATION ${CMAKE_CURRENT_BINARY_DIR})
+file(COPY ${test_resources_dir_name}
+  DESTINATION ${CMAKE_CURRENT_BINARY_DIR})