`x86_64-sie-ps5` is the triple we share with PS5 toolchain users who
have reason to care about such things. The vast majority of PS5 checks
and tests already use this variant. Quashing the handful of stragglers
will help prevent future copy+paste of the discouraged variant.
Adding a module flag 'MaxTLSAlign' describing the maximum alignment a global TLS
variable can have. Optimizers are prevented from increasing the alignment of such
variables beyond this threshold.
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D140123