GROOVY-6274: replaceNode improvements for XML processing
Fix for Lazy soft=true

Ensure @Lazy field is volatile

Soft References are always volatile, plus basic tests

remove automatic volatility from soft lazy variables

Fixed test (no volatility unless specified in source for soft lazy variables)
Merge pull request #145 from timyates/GROOVY-6056

GROOVY-6056 Fix for Lazy soft=true