[SPARK-19113][SS][TESTS] Ignore StreamingQueryException thrown from awaitInitialization to avoid breaking tests

## What changes were proposed in this pull request?

#16492 missed one race condition: `StreamExecution.awaitInitialization` may throw fatal errors and fail the test. This PR just ignores `StreamingQueryException` thrown from `awaitInitialization` so that we can verify the exception in the `ExpectFailure` action later. It's fine since `StopStream` or `ExpectFailure` will catch `StreamingQueryException` as well.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16567 from zsxwing/SPARK-19113-2.

(cherry picked from commit c050c122)
Signed-off-by: Shixiong Zhu <shixiong@databricks.com>