Pre-Charge max size when contracts access storage

[athei]

Previously, we assumed that the size of a storage item can be accessed in constant time (not dependent on the item's size). However, this turns out to be untrue.

What we need to do every time we access a variable sized storage item:

• Pre charge the maximum size this item can have from the gas meter before accessing it
• Refund after reading the value and the real size of the item is known

This applies to:

• Loading code for execution
• Loading pristine code for re instrumentation
• Reading contract values
• Writing contract values (the previous size needs to be known for storage deposits)
• Clearing contract values

This is also needed for #10301 because when reading the length of a storage value this requires the whole item to be included into the PoV.