Remove buildStatic from checks

checks should be relatively fast, but buildStatic depends on a lot of
stuff that isn't in the binary cache (e.g. musl builds of Git and
Mercurial that we probably don't need since we don't link against
them...).

flake.nix

@@ -440,8 +440,6 @@
       checks = forAllSystems (system: {
         binaryTarball = self.hydraJobs.binaryTarball.${system};
         perlBindings = self.hydraJobs.perlBindings.${system};
-      } // nixpkgs.lib.optionalAttrs (builtins.elem system linuxSystems) {
-        buildStatic = self.hydraJobs.buildStatic.${system};
       });
 
       packages = forAllSystems (system: {