dialogflow: remove unused samples and tests

[Strykrol]

Tests are currently unaltered, as the tests have variable dependencies. An example being the listContexts function stores a count into a contexts variable, which is then used to verify deleteContext functions as expected.

If I can get help refactoring test files that would be great. Otherwise, I will take a stab at them later this week.

[lesv]

A lot of ML samples need to be very loosely tested as the technology often changes underneath us.
I put a "do not merge" tag until you get the tests back.

[lesv]

Apparently I wasn't thinking when I commented yesterday.

[nnegrey]

Assigning to myself to get the tests updated for these.

[nnegrey]

@Strykrol should there be more deletions than just the list methods?
I'm gonna break up the tests into individual files.

[Strykrol]

@nnegrey - Yes, I will add those momentarily and update the PR.

[Strykrol]

@nnegrey - Added the remaining deletions (which generally deleted their entire containing files).

You're good to go with test refactoring, thank you for helping out.

[nnegrey]

@Strykrol, um mind pulling down the latest changes then just merging in master to the branch?

I was trying to do it, but just ended up creating a new branch on here. https://github.com/GoogleCloudPlatform/java-docs-samples/tree/Strykrol-snippetCleanup

[gguuss]

LGTM when tests pass.

[nnegrey]

Closing, something got lost in this PR and the tests are not finishing.
I've opened this one #2602 that I can directly edit.