Integration test refactoring

[dwitry]

• Test data refactoring
  • Externalized creation of "Modern Graph" to allow simple assertions on elements
  • Majority of tests don't need "Modern Graph", change default to empty graph
• Integration tests improvements
  • Avoid reserved names on different platforms (label, property)
  • Ignore result order where possible
• Create test suite for integration tests without extensions
• Speed up tests by starting Gremlin Server for test class instead of method

Signed-off-by: Dwitry dwitry@users.noreply.github.com