Undo PokeCodec's PRs

This commit undoes most of PokeCodec's PRs after the debate in chat. Some
harmless or completely superseded PRs have been left alone, as there is not
much benefit in attempting to undo them.

Reverts #1104, #1108, #1115, #1118, #1119, #1124, #1126, #1127, #1132, #1136,
#1137, #1139, #1140, #1144, #1148, #1149, #1150, #1153, #1155, #1177, #1179,
#1180, #1181, #1182 and #1183.

include/battle_main.h

@@ -73,6 +73,8 @@ void nullsub_20(void);
 void BeginBattleIntro(void);
 void SwitchInClearSetData(void);
 void FaintClearSetData(void);
+void sub_803B3AC(void); // unused
+void sub_803B598(void); // unused
 void BattleTurnPassed(void);
 u8 IsRunningFromBattleImpossible(void);
 void SwitchPartyOrder(u8 battlerId);
@@ -81,7 +83,6 @@ u8 GetWhoStrikesFirst(u8 battlerId1, u8 battlerId2, bool8 ignoreChosenMoves);
 void RunBattleScriptCommands_PopCallbacksStack(void);
 void RunBattleScriptCommands(void);
 bool8 TryRunFromBattle(u8 battlerId);
-void SpecialStatusesClear(void);
 
 extern struct UnknownPokemonStruct4 gMultiPartnerParty[MULTI_PARTY_SIZE];