[llvm] [MC,COFF] .safeseh: avoid changeSection (PR #132624)

[LIU Hao via llvm-commits]

lhmouse wrote:

`.safeseh` is not invented by LLVM; it's invented by Microsoft: https://learn.microsoft.com/en-us/cpp/assembler/masm/dot-safeseh?view=msvc-170

It creates some metadata (indexes of symbols to safe exception handlers) in the `.sxdata` section.


https://github.com/llvm/llvm-project/pull/132624