Moves the per-form routing (compile when :compile?, stateful forms always
interpret, interpreter fallback for uncompilable forms) into loader as
eval-toplevel, used by both load-ns and api/eval-one. Previously load-ns's
compile path called compile-and-eval directly with no fallback and no
stateful-form handling, so it would have broken ns/require/defmacro under
compile-by-default.
Array forms whose head is not a symbol (e.g. ((fn ...) args)) compile like
any other call, matching the prior eval-one behavior.
acf724b638