Support to specify jvm_heap_size option for ONOS container.
This allows to override the inferred defaults based on system memory.
manifest.json option is jvm_heap_size and defaults to 1 gig.
Run time command line setup/run option defaults to inferred mode as earlier done based on half of available system memory(capped to 16 gig)

Change-Id: I80a9180ad3a690fcef79d3c2979348965cda38b5
diff --git a/src/test/setup/manifest.json b/src/test/setup/manifest.json
index 8ac08e3..862662d 100644
--- a/src/test/setup/manifest.json
+++ b/src/test/setup/manifest.json
@@ -3,5 +3,6 @@
     "olt": true,
     "start_switch": true,
     "onos_image": "onosproject/onos:latest",
-    "log_level" : "INFO"
+    "log_level" : "INFO",
+    "jvm_heap_size" : "1G"
 }