8130425: libjvm crash due to stack overflow in executables with 32k tbss/tdata

Reviewed-by: kevinw, dholmes
Contributed-by: cheleswer.sahu@oracle.com

src/solaris/classes/java/lang/UNIXProcess.java

@@ -225,9 +225,8 @@ final class UNIXProcess extends Process {
             ThreadGroup systemThreadGroup = tg;
 
             ThreadFactory threadFactory = grimReaper -> {
-                // Our thread stack requirement is quite modest.
-                Thread t = new Thread(systemThreadGroup, grimReaper,
-                                      "process reaper", 32768);
+                long stackSize = Boolean.getBoolean("jdk.lang.processReaperUseDefaultStackSize") ? 0 : 32768;
+                Thread t = new Thread(systemThreadGroup, grimReaper,"process reaper", stackSize);
                 t.setDaemon(true);
                 // A small attempt (probably futile) to avoid priority inversion
                 t.setPriority(Thread.MAX_PRIORITY);