Update test id envvar to proper spelling

src/libexec/jattool-runtest

     #
     # Wrap in boilerplate and run test code in $1
     #
-    JAT__TESTID=$TestId jattool qrun "./test"
+    JAT__TEST_ID=$TestId jattool qrun "./test"
 }
 
 JATS__PATH=${JATS__PATH:-/usr/share/jat/suite}