Add X-CF-PROCESS-INSTANCE header tests for routing

[Samze]

• X-CF-PROCESS-INSTANCE:<process_guid>
• X-CF-PROCESS-INSTANCE:<process_guid>:<instance_index>

note This should not be merged until the work has been complete in GoRouter and released in cfd.

Are you submitting this PR against the develop branch?

Yes

What is this change about?

Add CATs test for ability to route to a specific process and process instance.

Please provide contextual information.

• https://github.com/cloudfoundry/gorouter/pull/467/files

What version of cf-deployment have you run this cf-acceptance-test change against?

• https://github.com/cloudfoundry/cf-deployment/releases/tag/v48.7.0

Please check all that apply for this PR:

• [x] introduces a new test --- Are you sure everyone should be running this test?
• [ ] changes an existing test
• [ ] requires an update to a CATs integration-config

Did you update the README as appropriate for this change?

• [x] YES
• [ ] N/A

How many more (or fewer) seconds of runtime will this change introduce to CATs?

Ran 1 of 250 Specs in 136.660 seconds
SUCCESS! -- 1 Passed | 0 Failed | 2 Pending | 247 Skipped
PASS | FOCUSED

What is the level of urgency for publishing this change?

• [ ] Urgent - unblocks current or future work
• [x] Slightly Less than Urgent

[Samze]

cc @tcdowney

[Samze]

Implemented PR https://github.com/cloudfoundry/gorouter/pull/467/files

[Samze]

Added in routing release 0.332.0, waiting for inclusion in cf-d.

[Samze]

Added to https://github.com/cloudfoundry/cf-deployment/releases/tag/v48.7.0