add a set of asserts to test.test_capi.test_bytearray
1. Assert empty bytearray object for PyByteArray_Check.
2. Assert empty bytearray object for PyByteArray_CheckExact.
3. Assert 0-size bytearray object for PyByteArray_Size.
4. Assert empty bytearray object for PyByteArray_AsString.
5. Assert concatenation of the bytearray object with itself for PyByteArray_Concat.
Move the following files from Modules/_testcapi/ to
Modules/_testlimitedcapi/:
* bytearray.c
* bytes.c
* pyos.c
* sys.c
Changes:
* Replace PyBytes_AS_STRING() with PyBytes_AsString().
* Replace PyBytes_GET_SIZE() with PyBytes_Size().
* Update related test_capi tests.
* Copy Modules/_testcapi/util.h to Modules/_testlimitedcapi/util.h.
Nybblista