Revert "Abstract methods aren't implementations."

This reverts commit 4a4d277a8cdfdd6e70e79b07266a79da33c78c3d.
Revert "Fix -Xjitthreshold (for real this time)."

This reverts commit c2f148bc26f30ea460aa2657dc8c1fe257c2cd57.
Revert "Fix -Xjitthreshold."

This reverts commit e3eff850fcbe46324dc44513e24c824bea8fb7d4.