Restore ios64_compile to the CQ.

See if it works now that
https://boringssl-review.googlesource.com/c/16150/ is in.

Change-Id: I082f4826d1a2d8688664ce2f24a5ad561e4c41c4
Reviewed-on: https://boringssl-review.googlesource.com/16204
Reviewed-by: Steven Valdez <svaldez@google.com>

infra/config/cq.cfg

@@ -61,9 +61,7 @@ verifiers {
       builders { name: "linux_fips_noasm_asan" }
 
       builders { name: "ios_compile" }
-      # TODO(davidben): Restore this builder once it's been switched to a
-      # newer macOS version.
-      # builders { name: "ios64_compile" }
+      builders { name: "ios64_compile" }
 
       builders { name: "android_arm_compile" }
       builders { name: "android_aarch64_compile" }