0024836: Stack overflow when raising exception in low memory condition

0024836: Stack overflow when raising exception in low memory condition

Standard_OutOfMemory exception is refactored so as to avoid memory allocations (which will likely fail) when it is raised:

- method NewInstance() returns static instance (singleton)
- method Raise() raises copy of that singleton, resetting its message string
- message string is stored as field, not allocated dynamically (thus maximum message length is limited by buffer size)

Class Standard_Failure slightly revised: method Destroy() is merged to destructor, methods Get/SetMessageString() are made virtual.

Add test case for the bug