[tsan] Another attempt to fix GCC 8.3 build after D107911

This removes the -Werror compilation flag for x64 linux to work around a gcc bug.

GCC 8.3 reports '__tsan::v3::Event::type’ is too small to hold all values of ‘enum class __tsan::v3::EventType’
incorrectly which gets promoted to an error and causes the build to fail.