<pthread.h> fixes and pthread cleanup.

<pthread.h> was missing nonnull attributes, noreturn on pthread_exit,
and had incorrect cv qualifiers for several standard functions.

I've also marked the non-standard stuff (where I count glibc rather
than POSIX as "standard") so we can revisit this cruft for LP64 and
try to ensure we're compatible with glibc.

I've also broken out the pthread_cond* functions into a new file.

I've made the remaining pthread files (plus ptrace) part of the bionic code
and fixed all the warnings.

I've added a few more smoke tests for chunks of untested pthread functionality.

We no longer need the libc_static_common_src_files hack for any of the
pthread implementation because we long since stripped out the rest of
the armv5 support, and this hack was just to ensure that __get_tls in libc.a
went via the kernel if necessary.

This patch also finishes the job of breaking up the pthread.c monolith, and
adds a handful of new tests.

Change-Id: Idc0ae7f5d8aa65989598acd4c01a874fe21582c7

libc/bionic/pthread_create.cpp

@@ -82,13 +82,12 @@ void  __init_tls(pthread_internal_t* thread) {
   }
 }
 
-__LIBC_ABI_PRIVATE__
 int _init_thread(pthread_internal_t* thread, bool add_to_thread_list) {
   int error = 0;
 
   // Set the scheduling policy/priority of the thread.
   if (thread->attr.sched_policy != SCHED_NORMAL) {
-    struct sched_param param;
+    sched_param param;
     param.sched_priority = thread->attr.sched_priority;
     if (sched_setscheduler(thread->tid, thread->attr.sched_policy, &param) == -1) {
 #if __LP64__