Check HTTP response headers of Swift API in detail

All HTTP response headers for each Swift API are checked their existence
and style. For checking, create custom_matchers.py file in common directory
and implement specific matchers so that they can be reused.

Change-Id: I7dcd87c814cf657999796bda75482505112b4edb
Closes-Bug: #1240856
Merge "Check HTTP response headers of Swift API in detail"