relax test expectation for 8.2

[remicollet]

Without:

TEST 7/10 [tests/021.phpt]
========DIFF========
001+ Warning: PHP Request Startup: open_basedir already set! Please unset open_basedir and only use realpath_turbo.open_basedir option. realpath_turbo will not have any effect when open_basedir is already set. in Unknown on line 0
001- Warning: Unknown: open_basedir already set! Please unset open_basedir and only use realpath_turbo.open_basedir option. realpath_turbo will not have any effect when open_basedir is already set. in %s on line %d
     
     Warning: request_startup() for realpath_turbo module failed in %s on line %d
========DONE========
FAIL realpath_turbo: Option realpath_turbo.open_basedir (set; with open_basedir already set) [tests/021.phpt]