tests/basic: Split tests into working with small ints and not working.

Tests which don't work with small ints are suffixed with _intbig.py. Some
of these may still work with long long ints and need to be reclassified
later.

tests/basics/int_bytes.py

@@ -1,7 +1,6 @@
 print((10).to_bytes(1, "little"))
 print((111111).to_bytes(4, "little"))
 print((100).to_bytes(10, "little"))
-print((2**64).to_bytes(9, "little"))
 print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))
 print(int.from_bytes(b"\x01\0\0\0\0\0\0\0", "little"))
 print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))