JDK 12 RFR of JDK-8207247: Reduce incidence of compiler.warn.source.no.bootclasspath in javac tests

[joe darcy]

Hello,

Please review the changes to address

     JDK-8207247: Reduce incidence of 
compiler.warn.source.no.bootclasspath in javac tests
     http://cr.openjdk.java.net/~darcy/8207248.0/

While working on the changes to prepare for removal of 
-source/-target/--release 6, some of the test edits that were need were 
to suppress extraneous warnings about -source/-target 7 being obsolete. 
To avoid a similar round of extraneous changes when -source/-targer 7 is 
removed and 8 becomes obsolete, this patch includes -Xlint:-options to 
remove the options-related warnings. The set of removed warnings 
includes the identified bootclasspath warning and will also cover future 
"-source/-target 8 is obsolete" warnings.

Thanks,

-Joe