[BLST] Remove heap allocation on aggregateVerify

[mratsim]

Currently this is needed:

https://github.com/status-im/nim-blscurve/blob/847f31d53007ed6e7d29c386150ff7a81860590a/blscurve/blst/bls_sig_min_pubkey_size_pop.nim#L549-L574

The context is ref or we have corrupted results

[mratsim]

This actually might not be possible, The C++ and Rust wrapper allocates on the heap:

• https://github.com/supranational/blst/blob/d661d16655385b6d5d0dcabbd09995c2cae131e8/bindings/blst.hpp#L365
• https://github.com/supranational/blst/blob/d661d16655385b6d5d0dcabbd09995c2cae131e8/bindings/rust/src/lib.rs#L28-L41