Fix a bug that the EC2 instance is not terminated if unit tests failed

[wanliAlex]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  bug fix

• What is the current behavior? (You can also link to an open issue here)
  The EC2 instance is not terminated if unit tests failed

• What is the new behavior (if this is a feature change)?
  I have verified that:

1. If a unit tests run is needed and it failed, the ec2 instance will be terminated;
2. If a unit tests run is not needed, no ec2 instance will be started and the termination job won't run.

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

• Have unit tests been run against this PR? (Has there also been any additional testing?)

• Related Python client changes (link commit/PR here)

• Related documentation changes (link commit/PR here)

• Other information:

• Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes/features)
• Docs have been added / updated (for bug fixes / features)