closes bpo-16637: libpython: construct integer object directly from gdbvalue (GH-15232)

This fixes the exception '`ValueError: invalid literal for int() with base 10`
if `str(gdbval)` returns a hexadecimal value (e.g. '0xa0'). This is the case if
the output-radix is set to 16 in gdb. See
https://sourceware.org/gdb/onlinedocs/gdb/Numbers.html for more information.

Tools/gdb/libpython.py

@@ -1392,7 +1392,7 @@ class wrapperobject(PyObjectPtr):
 
 
 def int_from_int(gdbval):
-    return int(str(gdbval))
+    return int(gdbval)
 
 
 def stringify(val):