Debug session cannot update their exception, and then provides the debugger incorrect information about the execution state

[StevenCostiou]

Bug description
The exception associated with the debug session of an opened debugger is not updated after its first initialization, while it can actually change to a new exception when an exception is raised during stepping operations.

This is because the exceptions in the simulator are captured and discarded.
Because the session and the simulator are extremely weakly coupled (which is good), there is no way the session can actually know an exception was raised but captured by the simulator.

The problem is the debugger uses the session and the known exception by the session to make assumptions about the execution state, and give appropriate tools.

A nice possibility would be to move the exception instance variable from the session to the process.
The exception would be easily updateable when raised during a process execution, and the process is known by the session that can just ask for the latest exception.

This requires:

• checking for side effects
• updating all debugging code using the exception from the session (if necessary)
• updating many of tests

Expected development cost
A few days.