[Develop] Support all BK/Travis cases in Submodule Regression Script

[NorseGaud]

Problems:

1. When manually running a forked PR using pull/7924/head:develop-submodule-regression-fix, the script will fail to use the merged commit for that forked PR.
2. git log logic wasn't working and throwing exit 1

Solutions:

1. Support if the PR slug exists (it's a forked PR) by doing git fetch/checkout of the ghost/merged commit.
2. Added no-pager and changed the logic to wrap in test

Travis

• Manual branch (no PR):
  • Skipped: https://travis-ci.com/EOSIO/eos/jobs/236551632
• PR branch:
  • Doesn't run...
• Manual PR branch:
  • Skipped: https://travis-ci.com/EOSIO/eos/jobs/236551632
• Forked PR branch [Develop] forked submodule regression fixes #7924:
  • PASS: https://travis-ci.com/EOSIO/eos/jobs/236503103
  • FAIL: https://travis-ci.com/EOSIO/eos/jobs/236218853
• Manual Forked PR branch [Develop] forked submodule regression fixes #7924:
  • Can't run?

Buildkite

• Manual branch (no PR):
  • Same branches: https://buildkite.com/EOSIO/eosio/builds/17592#554e460e-0dd1-4ef7-9301-ec9fa5e0e48c
• PR branch: [Develop] submodule regression fixes #7932:
  • PASS: https://buildkite.com/EOSIO/eosio/builds/17620#0ac3f53f-ec8d-407c-a99e-b489c315d0d5
  • FAIL: https://buildkite.com/EOSIO/eosio/builds/17623#a4055444-b080-4148-81fd-7dee8f61b4bc
• Manual PR branch [Develop] submodule regression fixes #7932:
  • Skip: https://buildkite.com/EOSIO/eosio/builds/17626#ac14ed47-6b98-4e28-8531-f6f674bee882
• Forked PR branch [Develop] forked submodule regression fixes #7924:
  • Doesn't run...
• Manual Forked PR branch [Develop] forked submodule regression fixes #7924:
  • Skip: https://buildkite.com/EOSIO/eosio/builds/17625#58677818-5cfd-498a-975e-6923293d4df0

[NorseGaud]

1.8.x: #7936
1.7.x: #7938

[NorseGaud]

Submodule running in travis (with if at end) works: https://travis-ci.com/EOSIO/eos/jobs/236503103