RFR JDK-8209605: com/sun/jdi/BreakpointWithFullGC.java fails with ZGC

[Alex Menkov]

Hi all,

please review a fix for
https://bugs.openjdk.java.net/browse/JDK-8209605
webrev:
http://cr.openjdk.java.net/~amenkov/sh2java/step1_zgc/webrev/

The fix:
- updates the fix so it works as original shell test:
   - drops "-Xmx32m" argument for debuggee (for shell test default jtreg 
-Xmx512m was effective);
   - drops requirement for "Pause Full (System.gc())" (different GCs use 
different logging, original test does not require it);
- fixes "ArrayIndexOutOfBoundsException: Index 0 out of bounds for 
length 0". The cause of the issue is String.split(sep), which can 
returns zero-length array;
- improve error handling - debuggee must be terminated if jdb execution 
fails.

--alex