Temporary warehouse on local is not a valid hdfs path (SharedSparkContext)

If a given test class is using SharedSparkContext and the main application points to an hdfs cluster by default, the application tries to initialize the temporary warehouse in a local directory. Since the local directory is not a valid hdfs path, the test fails. Warehouse should point to file://[whatever] instead of something like C://[whatever]

Start by tracing SharedSparkContext's temporary warehouse initialization and inspect the tests that use it. Confirm how the application resolves a local warehouse when the default points to HDFS, then verify affected tests pass with a file:// warehouse path.

Written by the indexing model from the issue text.