This is a partial backport of secp256k1#988
https://github.com/bitcoin-core/secp256k1/pull/988/commits/22dc2c0a0dc3b321e72253f492cfa8bcbf00169b
Note that this diff breaks the rust wrapping of the secp256k1 library and all the monorepo modules that depend on that rust wrapping. But everything is fixed again later in the same backport (D19400) when the precomputed table is included in the repo.