[llvm] [AsmPrinter][Dwarf5][nfc] Remove template from AccelTable class (PR #76296)

[Felipe de Azevedo Piovezan via llvm-commits]

felipepiovezan wrote:

> SGTM - if you're feeling so inclined, I wouldn't mind a quick summary of why this did exist and what made it no longer needed - but it's not super important if it's no longer needed in any case.

This was introduced in 2018 by @JDevlieghere in 98062cb396f4094f19321e55480d5488bed61f43
I believe the idea is that, for dsymutil, Entry data was stored by using a pointer to a DIE  instead of as individual bits of information (DIE offset, etc...).

Recently, these different implementations were combined by using a `std::variant`.

https://github.com/llvm/llvm-project/pull/76296