Limit Max Vector alignment on COFF targets to 8192.

COFF targets have a max object alignment of 8192, so trying to create
one with a larger size results in an unreachable in WinCOFFObjectWriter.

For the reproducer I have uses thread local storage, however other
alignments are likely affected as well.

This patch sets the MaxVectorAlign for COFF to 8192.  Additionally,
though there is no longer a way to reproduce that I could find, it
correctly sets the MaxTLSAlign for COFF to that value as well, so that
if anyone comes up with a situation where this is true, it will cause an
error.

Differential Revision: https://reviews.llvm.org/D85543