hg: jdk9/hs-rt/hotspot: 8054194: jstack crash: assert(handle != NULL) failed: JNI handle should not be null

[dmitry.samersoff at oracle.com]

Changeset: 474605fb56a4
Author:    dsamersoff
Date:      2014-09-25 02:48 -0700
URL:       http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/474605fb56a4

8054194: jstack crash: assert(handle != NULL) failed: JNI handle should not be null
Summary: Add better error check to sa to avoid secondary crash
Reviewed-by: sla, jbachorik, sspitsyn

! agent/src/os/win32/windbg/sawindbg.cpp