RFR(s): 8149036: Add UL tracing for thread related events at os level

[Thomas Stüfe]

Dear all,

please take a look at this proposed addition to UL. This adds a number of
trace points to thread creation. In detail:

- it traces thread creation and thread creation errors, including pthread
attributes (for Posix platforms)
- it traces stack location and creation/removal of stack guard pages.

This all was first AIX-only tracing, but I converted this to UL and made it
available on all platforms.

Bug: https://bugs.openjdk.java.net/browse/JDK-8149036
Webrev:
http://cr.openjdk.java.net/~stuefe/webrevs/8149036-add-tracing-for-thread-events/webrev.00/webrev/

Note also that I added a helper function, os::errno_name(), which is a very
simple replacement for strerror() without its problems (thread safety,
unwanted localizations...).

What do you think?

Kind Regards, Thomas