Summary:
1. Blacklist some upstream postgres files that do not properly follow
the leading_whitespace rule.
1. Fix all leading_whitespace lint errors. This involves some other
lint fixes in the area of those fixes.
Jira: DB-14604
Test Plan:
On Almalinux 8, zsh:
[ -z "$(git ls-tree --name-only -rz HEAD -- src/postgres \
| xargs -0 arc lint \
| grep leading_whitespace)" ]
Close: #25375
Jenkins: compile only
Reviewers: patnaik.balivada
Reviewed By: patnaik.balivada
Subscribers: patnaik.balivada, ycdcxcluster, yql
Differential Revision: https://phorge.dev.yugabyte.com/D40786