Make TextIOTest and AvroIOTest runner-agnostic

PipelineOptions contains a tempLocation property, and IOChannelUtils should be capable of handling arbitrary file locations that are used as a tempLocation.

The read and write tests for TextIO and AvroIO can use these properties to be written in a runner-agnostic fashion, and then be marked as RunnableOnService. Doing so allows all runners integrated with RunnableOnService to benefit from the existing tests.

Imported from Jira [BEAM-181](https://issues.apache.org/jira/browse/BEAM-181). Original Jira may contain additional context.
Reported by: tgroh.

Start with TextIOTest and AvroIOTest, then read PipelineOptions and IOChannelUtils to understand how tempLocation and arbitrary file locations are handled. Update the read and write tests to use these properties without depending on a specific runner, mark them RunnableOnService, and verify that the shared tests run successfully across integrated runners.

Written by the indexing model from the issue text.