Fix buffer size and alignment issues in api.buffer

Fix buffer size and alignment issues in api.buffer

- Don't use maxTexelBufferElements, it doesn't apply here
- Remove unused throw/catch blocks (catch block was never reachable)
- Add a case that exercises huge buffer sizes
- Add a check for sparseAddressSpaceSize

Modified tests:
- dEQP-VK.api.buffer.create_buffer_*

Fixes #558

Change-Id: Ia6b46d8c34a4eef4a6136532d0cb626d0b64b560