Review request: add TESTVMOPTS to jigsaw shell tests

[Mandy Chung]

The jigsaw shell tests currently ignore the VM options even if they are 
set via jtreg options (e.g. -client, -server, -esa, -ea, -vmoption or 
-vmoptions).  This patch fixes them up by adding TESTVMOPTS environment 
variable [1] that will be set to the VM options passed from the jtreg 
harness invocation:

Webrev at:
   http://cr.openjdk.java.net/~mchung/jigsaw/webrevs/test-vm-opts/

Mandy
[1] http://openjdk.java.net/jtreg/tag-spec.txt