fad1c55301 lint: Skip COMMIT_RANGE if no CIRRUS_PR (MarcoFalke)
Pull request description:
It doesn't make sense to run this for non-PRs, because:
* There are known whitespace "violations" in previous commits, so the lint may fail
* Once the changes are merged, it is too late to fix them up (force pushes are illegal)
* It isn't possible to determine which commits to run on if there is no reference branch (target branch of the pull request)
Moreover, the test fails on non-master:
* https://github.com/bitcoin/bitcoin/runs/8664441400
Fix all issues by skipping it.
ACKs for top commit:
hebasto:
ACK fad1c55301, also tested in my personal Cirrus account.
Tree-SHA512: be15f00e2b2a9069583833545883e0e5968a33d2455dad59e6fb47c1102b4dd16ef932e9ba945e29e9d941e6c17bd531a02c66b0491097801be6bda476875537