Avoid changing global state in CI runs II (#21643)

* Avoid changing global state in CI runs II
  - move `dotnet` tools into `$PWD/.dotnet/tools/`
    - add `dotnet` tools to `$env:PATH`
  - install `jq` in `$PWD/.tools/`
  - install `nginx` in `$PWD/.tools/nginx/`

nits:
- remove an extra (incorrect) `$env:JAVA_HOME` setting
  - build.ps1 finds a local JDK and sets this variable (and `$env:PATH`) properly
- avoid `'$(SELENIUMPROCESSTRACKINGFOLDER)' == '\artifacts\tmp\selenium\'`
  - `$(BuildDirectory)` was normally the empty string (w/o fix)
  - use `$(BuildDirectory)` a bit more

* Add files. disable artifact / test results publications to avoid warnings on CI
  - artifacts/log is often empty when binary logs are disabled
  - no tests create *.trx files
    - don't have Java test results either
  - only test jobs need test results published