RFR 8153123 : Streamline StackWalker code

[Brent Christian]

Hi,

I'd like to check in some footprint and code reduction changes to the 
java.lang.StackWalker implementation.

Webrev:
http://cr.openjdk.java.net/~bchristi/8153123/webrev.00/
Bug:
https://bugs.openjdk.java.net/browse/JDK-8153123

A summary of the changes:

* remove the "stackwalk.newThrowable" system property and 
"MemberNameInStackFrame" VM flag, originally left in to aid benchmarking

* Streamline StackFrameInfo fields

* Refactor/streamline StackStreamFactory (no more separate 
classes[]/StackFrame[] arrays, remove unneeded (for now) 
StackStreamFactory.StackTrace class)


Given the hotspot changes, I plan to push this through hs-rt.

Thanks,
-Brent