Remove -enable-ed25519 compat hack.

Change-Id: I2d5843b2dc957f8ae8e4d9a41cecd3268220cc1d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/41504
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/ssl/test/test_config.cc b/ssl/test/test_config.cc
index ad8ecdb..d4b71b4 100644
--- a/ssl/test/test_config.cc
+++ b/ssl/test/test_config.cc
@@ -307,12 +307,6 @@
     return true;
   }
 
-  if (strcmp(flag, "-enable-ed25519") == 0) {
-    // Old argument; ignored for split-handshake compat testing.
-    // Remove after 2020-06-01.
-    return true;
-  }
-
   fprintf(stderr, "Unknown argument: %s.\n", flag);
   return false;
 }