Full language coverage.

The remaining tasks should be driven by throw new UnsupportedOperationException in CpsTransformer.

• synchronized statements (maybe warn and ignore?)
• Method pointer expression
• List spread expression x=[2,3]; y=[1,*x,4]; assert y=[1,2,3,4]
• Map spread expression
• Spread method call: x = [1,2,3]; assert x*.toString() = ["1","2","3"]
• Safe method call: x=null; assert x?.foo()==null

See also comment in localMethodCallWithinLotsOfBranches.groovy.

Must also ensure that any exception in this area is properly reported as an error in the log, rather than simply killing the VM thread.