Verify that there aren't too many OAM constants

[Rangi42]

The oamframe macro declares an OAM ID (i.e. a SPRITE_ANIM_OAM_* or BATTLEANIMOAMSET_* constant (names to change pending #1055)). The last few IDs are reserved for non-frame commands ($FC oamdelete, $FD oamwait, $FE oamrestart, $FF oamend). The oam* macros should declare a constant for the last valid OAM frame ID, and assert that the numbers of sprite and battle OAM constants are not exceeding it.