GROOVY-7143: groovy.json.DateFormatThreadLocal creates a memory leak
Merge pull request #529 from PascalSchumacher/GROOVY-7143_DateFormatThreadLocal_memory_leak

GROOVY-7143: groovy.json.DateFormatThreadLocal creates a memory leak
Catch Throwable because some runtimes may throw exceptions which do not extend Exception (eg. Android)