Some more updates to PHP testing infrastructure (#8576)

* WIP.

* Added build config for all of the tests.

* Use ../src/protoc if it is available, for cases where Bazel isn't available.

* Added test_php.sh.

* Fix for the broken macOS tests.

* Move all jobs to use php80 instead of lots of separate jobs.

* Only pass -t flag if we are running in a terminal.

* Updated php_all job to use new Docker stuff.