Remove SecurityManager references from API code in response to JEP 411

[Rob McDougall]

JEP 411 deprecates Security Manager for future removal.

SecurityManager references appear throughout the API code. Specifically:
CommandInfo.java (3 matches)
CommandMap.java (3 matches)
DataHandler.java (3 matches)
FileTypeMap.java (3 matches)
MailcapCommandMap.java
MimetypesFileTypeMap.java
ServiceLoaderUtil.java (2 matches)