When -O2 and -fstack-protector-all are added together in clang, the tail call optimization will be disabled.
See here https://godbolt.org/z/bffPPv3zh
Because opt only emit ssqreq and tail call attribute for them,
and theses optimizations are handled by llc exactly.
So in this patch, I would like to release the condition in StackProtector.
Even for tail call (not musttail call), both stack protection and TCO(tail call optimization) will be enabled.
And finally, clang will also benefit from this small change.