Fix failing tests

  * brooklyn.util.ResourceUtilsTest.testGetResourceViaClasspathWithoutPrefix() fails on windows paths when OSGi is used
  * Explicitly wait for osgi framework shutdown before deleting the cache folder so all files are unlocked
  * LocationUsageTrackingTest.testUsageIncludesStartAndStopEvents - the test excludes the start and stop ms from the range of possible values
  * Temporary file and folder creation wasn't deterministic, resulting in unexpected exceptions
  * UsageResourceTest - guarantee the 1ms delay that the test assumes at specific points (can't use dates in the future)
missing a `t` in `Attempt`

worth a comment that this collision is unlikely due to the `makeRandomId` but with lots of temp dirs it can start to happen ?

if the creation failed (`log.warn`), e.g. because a directory was not writable or disk is full, do we really want to retry 1000 times?  maybe set `ATTEMPTS` much lower?