[clang] Revert "[Clang] Fix missed initializer instantiation bug for variable templates" (PR #140930)

[Younan Zhang via cfe-commits]

zyn0217 wrote:

I'll go ahead and merge this: the eager instantiation of member templates - even it is still dependent - doesnt look right to me

In the meantime, I'll look into the case and see if I can figure out a solution

https://github.com/llvm/llvm-project/pull/140930