[10] RFR: JDK-8191350: jdk/internal/reflect/CallerSensitive/CheckCSMs.java test fails when -Xmx512m set

[mandy chung]

Test-only fix.

The CheckCSMs.java and CallerSensitiveFinder.java tests fail with OOME
when running with -Xmx512m.  The test intends to parse class files, one
per task in a thread pool but each task keeps a ClassFile that has done
the parsing and occupies the space.  This patch fixes the tests to delay
reading of the class file when the task is scheduled (i.e. the task
takes the path to the class file instead of ClassFile instance).

Webrev at:
http://cr.openjdk.java.net/~mchung/jdk10/webrevs/8191350/webrev.00/

Mandy