if all options from a combination from the combinations file are already
present in the server's list of options, then don't try to run tests
in other combinations from this file.

old behavior was: if at least one option from a combination is
already present in the list...

part II

need to tell SafeProcess not to collect the exited mysqld
in sleep_until_file_created(), so that it would be found in the
later wait_any_timeout() in run_testcase()

Removed a strange condition in SafeProcess::wait_one()
that treated return value of -1 from waitpid() as "process exists"
instead of as "no such child process" (see `perldoc -f waitpid`)

expect file is always removed before starting a server.
So if it exists here, it means the server started successfully,
mysqltest continued executing the test, created a new expect file,
and shut down the server. All while we were waiting for the server
to start.

In other words, if the expect file exists, the server did actually start.
Even if it isn't running now.

This fixes occasional failures of innodb.log_corruption (in 10.6)

to print all arguments of _verbose(), not just the number of them

if mysqld is restarted during a test, the debugger script
should be reused or overwritten, but not appended to the existing file

mysqltest has no --gdb option

use _RR_TRACE_DIR=dir instead of -o dir, as the former can store
multiple traces in dir (if, e.g., the test restarts mysqld)

suppress uninitialized warning when $exe is undefined (--manual-XXX)