Implement enough JDWP functionality that we can attach jdb.

You can also try "classes" and "classpath", though anything else
deadlocks because we're suspended but jdb thinks we aren't. I don't
think that's a new bug with this patch, though, so I'll look at that
next.

Change-Id: I54456b6a7fe72642be696c66aa485dc0c8a7f913
diff --git a/test/etc/push-and-run-test-jar b/test/etc/push-and-run-test-jar
index 53d7a76..1d10e4d 100755
--- a/test/etc/push-and-run-test-jar
+++ b/test/etc/push-and-run-test-jar
@@ -99,11 +99,11 @@
 
 if [ "$DEBUG" = "y" ]; then
   # This is for ddms:
-  DEX_DEBUG="-agentlib:jdwp=transport=dt_android_adb,server=y,suspend=y"
+  #DEX_DEBUG="-agentlib:jdwp=transport=dt_android_adb,server=y,suspend=y"
   # Connect by running 'ddms'.
 
   # This is for jdb:
-  #DEX_DEBUG="-agentlib:jdwp=transport=dt_socket,address=12345,server=y,suspend=y"
+  DEX_DEBUG="-agentlib:jdwp=transport=dt_socket,address=12345,server=y,suspend=y"
   # Connect thus:
   #   adb forward tcp:12345 tcp:12345
   #   jdb -attach localhost:12345