[HEADS UP] TEST_LWP_ENABLED in ATF t_ptrace_wait*

[Kamil Rytarowski <n54%gmx.com@localhost>]

I have bumped the number of threads in the t_ptrace_wait* LWP tests from
3 to 100. Each thread attempts to generate 1 or 2 SIGTRAP. 100 threads
struggling to emit 100 sigtraps generates complexity that affects timing
of execution.

Please report back whether the execution on low-end setups or software
emulation runs without timeouts. If there are timeouts please reduce
TRACE_THREADS_NUM from 100 to a smaller value and please report back
what is the reliable number.

If there are any failures in this setup, please report to me.

The purpose of keeping the TRACE_THREADS_NUM number as high as possible
is to torture the kernel and more frequently trigger any kernel anomalies.