E2E: Output all logs from SSM to S3 and read output from there

[vivek-koppuru]

If a test goes too long, the output from SSM gets truncated which results in our Lambda not being able to parse the output of the test for success or failure. Instead, we can have output from SSM go directly to a file in S3 and have CodeBuild and Lambda read from those files instead of from stdout to avoid limitations from SSM.