Battle events refresh and update logic is wrong

[fmatthew5876]

Create a 2k battle with 2 enemies. Give each enemy an action which enables switch 1.

Now create 2 copies of a battle event enabled by switch 1 with this code:

Msg: Hello
Switch 1 off

In RPG_RT, we get: Enemy attacks, "Hello", Other enemy attacks, "Hello"
In Player, we get: Enemy attacks, "Hello", "Hello", Other enemy attacks

This happens because in Game_Battle::RefreshEvents() we mark both pages as runnable and then later in Game_Battle::UpdateEvents() we run both.

Instead we need to have a single iteration which checks the page conditions and runs each page at the same time, so that we don't enable both events.

[fmatthew5876]

This bug is also present in 2k3 battles.

Page1, Enabled by SW1, Msg A, Sw1 Off
Page1, Enabled by SW1, Msg B, Sw1 Off

Use a skill that enabled SW1

RPG_RT: "A"
Player: "A", "B"