Reorder the `MethodType` enum values so that `METHOD_NONE` is placed last instead of first,
and correspondingly move the `METHOD_NONE` case in the interpreter's dispatch switch to the
end of the case list. This places the most frequently executed method types (`METHOD_PRIMITIVE`,
`METHOD_FOREIGN`, `METHOD_BLOCK`, `METHOD_CTOR`) earlier in both the enum and the switch,
which can improve branch prediction and instruction cache locality in the hot dispatch loop.
Bob Nystrom
5e62b5856e