Fix GT++ Energy Buffer NPE

[reobf]

Fix: GTNewHorizons/GT-New-Horizons-Modpack#16565

The bug is: Charge a GT++ Energy Buffer to full energy, save the game and load it again, there will be ERROR in log:

expand

[13:47:28] [Server thread/INFO] [FML]: Loading dimension 180 (New World) (net.minecraft.server.integrated.IntegratedServer@5e21656e)
[13:47:28] [Server thread/ERROR] [GregTech GTNH]: Encountered Exception while loading MetaTileEntity.
[13:47:28] [Server thread/ERROR] [GregTech GTNH]: java.lang.NullPointerException
	at gregtech.api.metatileentity.BaseTileEntity.func_70296_d(BaseTileEntity.java:567)
	at gregtech.api.metatileentity.CommonMetaTileEntity.func_70296_d(CommonMetaTileEntity.java:118)
	at gregtech.api.metatileentity.MetaTileEntity.func_70296_d(MetaTileEntity.java:1049)
	at gregtech.api.metatileentity.MetaTileEntity.setEUVar(MetaTileEntity.java:593)
	at gtPlusPlus.xmod.gregtech.common.tileentities.storage.MTEEnergyBuffer.loadNBTData(MTEEnergyBuffer.java:269)
	at gregtech.api.metatileentity.CommonMetaTileEntity.loadMetaTileNBT(CommonMetaTileEntity.java:100)
	at gregtech.api.metatileentity.BaseMetaTileEntity.setInitialValuesAsNBT(BaseMetaTileEntity.java:221)
	at gregtech.api.metatileentity.BaseMetaTileEntity.func_145839_a(BaseMetaTileEntity.java:173)
	at net.minecraft.tileentity.TileEntity.func_145827_c(TileEntity.java:116)
	at net.minecraft.world.chunk.storage.AnvilChunkLoader.loadEntities(AnvilChunkLoader.java:496)
	at net.minecraftforge.common.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:41)
	at net.minecraftforge.common.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:12)
	at net.minecraftforge.common.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:344)

This is caused by 'loadNBTData' invoking some method on 'worldObj' indirectly(which is still null when chunk is loading).

This happens if：

1. NBT tag 'aStoredEU' is present.
2. 'aStoredEU' != internal EU value

internal EU value might exceed the maximum, but 'aStoredEU' is strictly truncated to max EU storage
That's why the bug only happens when its chraged to full energy

This PR removes unnecessary saving of 'aStoredEU' in method 'saveNBTData', to prevent accessing 'worldObj' too early.
After fix, Energy Buffer will not lose its energy after save-n-load because internal EU value is already persisted in BaseMetaTileEntity.java.

GT5-Unofficial/src/main/java/gregtech/api/metatileentity/BaseMetaTileEntity.java

Line 145 in 96f2d08

nbt.setLong("mStoredEnergy", mStoredEnergy);

GT5-Unofficial/src/main/java/gregtech/api/metatileentity/BaseMetaTileEntity.java

Line 189 in 96f2d08

mStoredEnergy = aNBT.getLong("mStoredEnergy");

The function of keeping EU after harvested won't be affected, because 'loadNBTData' and 'setItemNBT' will still work.