Linux sandbox: report TSYNC status in chrome://sandbox
TSYNC is a new sandboxing flag for seccomp that was recently added to
the Linux kernel.
If TSYNC is supported by the kernel, it is automatically used when enabling
When seccomp-bpf is enabled, we now report if TSYNC is supported by the kernel
This allows users and developers to check their level of sandboxing and to
know how the sandbox has been enabled on their running instance of Chrome.