Python 3 doesn't have a distinction between PyInt and PyLong, it's all
PyLong now.
This also fixes a bug in SetNumberFromObject. This used to crash LLDB:
```
lldb -o "script data=lldb.SBData(); data.SetDataFromUInt64Array([2**63])"
```
The problem happened in the PyInt path:
```
if (PyInt_Check(obj))
number = static_cast<T>(PyInt_AsLong(obj));
```
when obj doesn't fit in a signed long, `PyInt_AsLong` would fail with
"OverflowError: Python int too large to convert to C long".
The existing long path does the right thing, as it will call
`PyLong_AsUnsignedLongLong` for uint64_t.
Differential Revision: https://reviews.llvm.org/D146590