Umbrella bug for missing and broken SA features on OSX

The purpose of this bug is to track all known missing and broken SA features on OSX. There are quite a few of them, pretty much none with filed bugs, and usually silently worked around in the tests. A list will be maintained below, with link to filed CRs if they exist.

1. There is no LoadObject support for processes on OSX. There is for core files. Because of this PMap and PStack will not work on processes since there is no list of LoadObjects for PMap to print and there is no list of LoadObjects for PStack to do address -> symbol lookup in.

2. Core file Address -> Symbol lookup is limited to JVM libraries: If the symbol is in a system or user library, or in the executable, it won't be found. See JDK-8248882 for some information as to why.

3. LoadObject sizes are incorrect: LoadObjects are created when debugging a core (as mentioned above, they are not when debugging a process), but the size of the LoadObject is not correct. It simply uses the file size. See BsdDebuggerLocal.createLoadObject(). Since the "textsize" argument is always 0 (the native code doesn't have the proper size info either), BsdDebuggerLocal.createLoadObject() does the next best thing and uses the file size. (This now fixed by JDK-8261710)

4. JDK-8239062: jhsdb jstack does not work with debugd server on OSX