Disable strace+debug when explicitly requested
Disable strace+debug when explicitly requested

Currently strace+debug is always enabled as the setting from
the upper layer isn't passed to _syscall_test(). And it will
negatively affect the performance tests. This patch fixes this
issue.

The "debug" argument of _syscall_test() is also made mandatory
to prevent this happening again.

//test/perf:getpid_benchmark_runsc_kvm

-----------------------------------------------------
Benchmark           Time             CPU   Iterations
-----------------------------------------------------
Before:
BM_Getpid       28119 ns        28157 ns        25926

After:
BM_Getpid         947 ns          939 ns       777778

Fixes #4509

Signed-off-by: Tiwei Bie <743644a4d6d61011bf2ed448b266f6fed94449a2@antgroup.com>

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor