Merge BadRequest tests of v2 quota_sets API

In test_quotas, there are BadRequest tests of v2 quota_sets API.
Most parts of them are duplicated.
This patch merges them for the readability and clarifying their purposes.

Change-Id: I4313b2a80819260e9363f457ba271689308b145f
Merge "Merge BadRequest tests of v2 quota_sets API"