Fixed "NoneType has no attribute 'item'" error

[M4tsuri]

Fixed the error "NoneType has no attribute 'item'"

[M4tsuri]

I was trying to analyse this simple program:

And then two problems occurred

1. If I launch the plugin before the first malloc function call, It will give me a "'NoneType' has no attribute 'item'" error when the first malloc() is called.
2. It will give me a "'NoneType' has no attribute 'count'" error when the first free() is called and stop updating heap info.

So I searched for the code and I found the 'get_tcache_address' function in ptmalloc.py is the cause. I edited it like this and reload the plugin, then all errors disappeared.
(I changed the return statement so that it won't return a None value)

And I got this in the console:

656 compare to 592
self.tcache_perthread_s: 576
self.malloc_alignment: 16

My change just makes it look better, however I'm not sure what this if statement has done

if chunk.norm_size == (sizeof(self.tcache_perthread_s) + self.malloc_alignment):

[danigargu]

Thanks! this commit seems to solve the issue ;)