Debugger should create function for the instruciton pointer inside of the debugger core

[xusheng6]

When the target stops at an address that does not have a function, the debugger creates a new function at the address to have the UI show the code. Right now, this is done by the debugger UI when it is about to do the navigation. So far so good, however, maybe we should consider doing it inside of the debugger core. A relevant issue is https://github.com/Vector35/debugger/issues/631, where the target stops at a code buffer on the heap. The stack trace information is collected before the function is created, and that causes the stack trace to not able to leverage the later-to-be-created function. That said, this might cause other issues since it will cause the analysis to be running when the debugger is collecting the info, which may cause other (and potentially more severe) issues. I am just creating this issue to track it and allow future consideration