Improve Use-Case for Patching Relocations with MemoryMap

[bpotchik]

Additional work required from original issue: #4950 While we have the ability to patch bytes in regions with relocations using the new MemoryMap, the current implementation is somewhat raw and can be improved for better usability and control. Here’s an example demonstrating the existing behavior:

>>> relo = bv.relocation_ranges[0]
>>> relo_size = relo[1] - relo[0]
>>> relo_size
4
>>> bv.read(relo[0], relo_size)
b'H\x10\x01\x00'
>>> bv.write(relo[0], b'\xff' * 4)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Applications/Binary Ninja.app/Contents/MacOS/plugins/../../Resources/python/binaryninja/binaryview.py", line 4232, in write
    raise RelocationWriteException("Attempting to write to a location which has a relocation")
binaryninja.exceptions.RelocationWriteException: Attempting to write to a location which has a relocation

# Note we do not define any permissions, the region will inherit the permissions from the existing shadowed region.
>>> bv.memory_map.add_memory_region("my_writable_relo", relo[0], b'\xff' * 4)
True
>>> bv.read(relo[0], relo_size)
b'\xff\xff\xff\xff'
>>> bv.write(relo[0], b'\xda' * 4)
4
>>> bv.read(relo[0], relo_size)
b'\xda\xda\xda\xda'

While this works, currently adding a memory region ends up modifying the segment map:

r-x  0x00008000-0x00008528 
rw-  0x00010f0c-0x0001100c 
rw-  0x0001100c-0x00011010  <<<< 4 byte segment for the relocation

Need to investigate the following:

• Implement a method to prevent segment bloat when patching relocations. Perhaps adding a hidden MemoryMap layer that handles patches and relocations separately from the main memory regions.
• Explore ways to automate the relocation patching process in the UI