1. Increased the timeout on sapi/fpm tests to match the cli server
2. Fixed user session GC function to return number of sessions removed
3. Disabled session GC in session_set_save_handler_basic.phpt
2d9885c introduced some regressions. This addresses those.
* Don't throw return type notice or session write failure when in an exception
* Fix tests to properly return true/false since null is no longer falsy/successy
* Rerecord a few tests to accomodate difference in raised warnings
These hopefully test a reasonable set of basic, error and variations for
the twenty or so session functions. Note however that they do not
test all the session configuration settings.
