Rename EHPersonality::MSVC_Win64SEH to EHPersonality::MSVC_TableSEH. NFC.

The types of SEH aren't x86(-32) vs x64 but rather stack-based exception chaining
vs table-based exception handling. x86-32 is the only arch for which Windows
uses the former. 32-bit ARM would use what is called Win64SEH today, which
is a bit confusing so instead let's just rename it to be a bit more clear.

Reviewed By: compnerd, rnk

Differential Revision: https://reviews.llvm.org/D90117