[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.

Author: dyung

compiler-rt/lib/tsan/go/buildgo.sh

@@ -59,7 +59,7 @@ if [ "`uname -a | grep Linux`" != "" ]; then
 	elif [ "`uname -a | grep x86_64`" != "" ]; then
 		SUFFIX="linux_amd64"
 		ARCHCFLAGS="-m64 -msse4.2"
-		OSCFLAGS="$OSCFLAGS -ffreestanding -Wno-unused-const-variable -Werror -Wno-unknown-warning-option"
+		OSCFLAGS="$OSCFLAGS -ffreestanding -Wno-unused-const-variable -Wno-unknown-warning-option"
 	elif [ "`uname -a | grep aarch64`" != "" ]; then
 		SUFFIX="linux_arm64"
 		ARCHCFLAGS=""