Add a mechanism to allow a CDS mode execution using jdk make system.

The goal is to execute arbitrary jtreg tests with use of CDS archive, to provide better testing for CDS.

This should work as follows:
 - user specifies an env variable for make to enable this mode: GENERATE_CDS_ARCHIVE=true
 - this will work with 'test' target
 - when this mode is in use, make will generate a CDS archive by running -Xshare:dump into a predefined location
 - during the test execution the shared archive will be in use, specifying -XSharedArchiveFile=<location-defined-by-make>
 - user is free to append additional arguments, as usual, such as "-Xshare:auto, -Xshare:on, -Xlog:class+path=trace, etc."

========= Example:
  make GENERATE_CDS_ARCHIVE=true \
     test TEST=$testset \
     JAVA_ARGS="-Xshare:auto -Xlog:class+path=trace -XX:+PrintSharedSpaces -showversion"