GHA: bump analyzer/sanitizer jobs to clang-22, and ubuntu-26.04

On Linux, and Windows cross-builds.

clang-tidy jobs look significantly faster. Other jobs remain around the
same (this feels nice after seeing the significant slowdowns in
Windows-2025, FreeBSD 15.)

Before: https://github.com/curl/curl/actions/runs/27770630688
After: https://github.com/curl/curl/actions/runs/27770913426?pr=22086

gcc-analyzer also got faster:
Before: https://github.com/curl/curl/actions/runs/27758865007/job/82127670883
After: https://github.com/curl/curl/actions/runs/27768696084/job/82162385765

Also:
- work around actionlint 1.7.12 not yet being aware of ubuntu-26.04:
  ```
  windows.yml:770:14: label "ubuntu-26.04" is unknown. available labels are [...]
  ```
  Ref: https://github.com/curl/curl/actions/runs/27769065782/job/82163700294#step:6:13
  Ref: https://github.com/rhysd/actionlint/issues/682
  Ref: https://github.com/rhysd/actionlint/pull/683

Follow-up to 5a2af800de #22084

Closes #22086

.github/workflows/checksrc.yml

@@ -174,7 +174,7 @@ jobs:
           eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
           export SHELLCHECK_OPTS='--exclude=1090,1091,2086,2153 --enable=avoid-nullary-conditions,deprecate-which'
           actionlint --version
-          actionlint --ignore matrix .github/workflows/*.yml
+          actionlint --ignore matrix --ignore ubuntu-26.04 .github/workflows/*.yml
 
       - name: 'shellcheck CI'
         run: |