Speed up grab command test

The autoconfiguration transformations (and loads of grabs
of spring-boot snapshots) were making the grab command
tests run really slowly. Snapshots are particularly bad.

Fixed by adding a --autoconfigure=false option to the
compiler configuration and using it in that test.

spring-boot-cli/src/test/resources/grab-samples/grab.groovy

@@ -1,4 +1,4 @@
-@Grab('spring-jdbc')
+@Grab('jopt-simple')
 class GrabTest {
 	
 }