`ql.mem.unmap_all` does not unmap all memory regions

[LukeSerne]

Describe the bug
Mapping a memory region starting at address 0 and then calling ql.mem.unmap_all does not unmap the region.

Sample Code

import qiling
from qiling.const import QL_ARCH

ql = qiling.Qiling(code=b"\0", archtype=QL_ARCH.ARM, ostype='linux')
ql.mem.map(addr=0, size=0x1000)
ql.mem.unmap_all()
assert ql.mem.map_info == [], ql.mem.map_info 

Actual behavior

$ python main.py
Traceback (most recent call last):
  File "main.py", line 7, in <module>
    assert ql.mem.map_info == [], ql.mem.map_info 
AssertionError: [(0, 4096, 7, '[mapped]', False)]

Expected behavior
No assertion error and the entire memory space is reclaimed (as the docstring says).

Additional context
This region is not unmapped because begin is 0, which causes the begin and end guard in the below code to be False. I am not sure why this check is even there - I think the if should be removed, and self.unmap should always be executed.

qiling/qiling/os/memory.py

Lines 417 to 423 in 59d31c2

	def unmap_all(self):
	"""Reclaim the entire memory space.
	"""
	for begin, end, _ in self.ql.uc.mem_regions():
	if begin and end:
	self.unmap(begin, end - begin + 1)

[wtdcode]

Good catch. :)

[wtdcode]

Closed due to PR merged.