Revert "Update BLST, add force-adx support (#1595)" (#1649)

This reverts commit 4fca306397.

Something in the BLST update is causing SIGILLs on aarch64 non-portable builds. While we debug the issue, I think it's best if we just revert the update.

lighthouse/Cargo.toml

@@ -9,9 +9,6 @@ edition = "2018"
 write_ssz_files = ["beacon_node/write_ssz_files"]
 # Compiles the BLS crypto code so that the binary is portable across machines.
 portable = ["bls/supranational-portable"]
-# Compiles BLST so that it always uses ADX instructions.
-# Compatible with processors from 2013 onwards.
-modern = ["bls/supranational-force-adx"]
 # Uses the slower Milagro BLS library, which is written in native Rust.
 milagro = ["bls/milagro"]
 

lighthouse/src/main.rs

@@ -16,8 +16,6 @@ pub const ETH2_CONFIG_FILENAME: &str = "eth2-spec.toml";
 fn bls_library_name() -> &'static str {
     if cfg!(feature = "portable") {
         "blst-portable"
-    } else if cfg!(feature = "modern") {
-        "blst-modern"
     } else if cfg!(feature = "milagro") {
         "milagro"
     } else {
@@ -183,13 +181,6 @@ fn run<E: EthSpec>(
         ));
     }
 
-    #[cfg(all(feature = "modern", target_arch = "x86_64"))]
-    if !std::is_x86_feature_detected!("adx") {
-        return Err(format!(
-            "CPU incompatible with optimized binary, please try Lighthouse portable build"
-        ));
-    }
-
     let debug_level = matches
         .value_of("debug-level")
         .ok_or_else(|| "Expected --debug-level flag".to_string())?;