Saltcheck allow multiple asserts against module output

[mchugh19]

What does this PR do?

Allows saltcheck tests to specify multiple assertions against module output

Previous Behavior

A saltcheck tests could only be defined like

test with complicated output:
  module_and_function: network.netstat
  assertion: assertEqual
  assertion_section: "0:program"
  expected_return: "systemd-resolv"
  output_details: True
  print_result: True

New Behavior

By creating a list under an assertions key, multiple asserts can be run

multiple checks on complicated output:
  module_and_function: network.netstat
  assertions:
    - assertion: assertEqual
      assertion_section: "0:program"
      expected_return: "systemd-resolve"
    - assertion: assertEqual
      assertion_section: "0:proto"
      expected_return: "udp"
  output_details: True
  print_result: True

Multiple assertions can be run against the output of a single module_and_function call. The assertion, expected_return, assertion_section, and assertion_section_delimiter keys can be placed in a list under an assertions key.

Tests written?

Yes

[mchugh19]

re-run pr-ubuntu1604-py3-pycryptodomex

[mchugh19]

re-run pr-windows2019-py3