Fix log_verbosity_bug.phpt

This test may fail on Windows due to the file cache fallback.  We
ensure that this will not happen.

Author: cmb69

ext/opcache/tests/log_verbosity_bug.phpt

@@ -8,6 +8,7 @@ The process should die regardless of the log_verbosity_level.
 opcache.enable=1
 opcache.enable_cli=1
 opcache.file_cache_only=0
+opcache.file_cache_fallback=0
 opcache.memory_consumption=999999999
 opcache.log_verbosity_level=-1
 --SKIPIF--