lshal: Fix timeout causes unexpected exits.

with thread::detach the background thread keeps running even after
the thread object is destroyed; the background thread will access
caller's stack memory, causing segfault. Change it to a thread join
to avoid the issue. To avoid waiting too long on the child thread,
send a SIGINT if timeout (child thread's signal handler will then
call pthread_exit() to terminate the thread).

Since we are using pthread_* functions, change usage of std::thread
to pthread_t for consistency.

Test: lshal
Test: run lshal with IPC_CALL_TIMEOUT set to zero will no longer
      cause SIGSEGV and SIGABRT (test 10 times)

Bug: 35623669
Change-Id: I4eef8ffd8ff399793648e861ca4c1a2bdcc7ec50