RFR[12] JDK-8209546: Make sun/security/tools/keytool/autotest.sh to support macosx

[sha.jiang at oracle.com]

>>
>> 2. Is launching a separate process necessary? Can we just call 
>> KeyToolTest::main after setting system properties and copying the files.
> I did think about this point.
> It looks this test could be run by manual if someone want to set those 
> system properties.
> I supposed that's why KeyToolTest.java is not a jtreg test.
I misunderstood this point.
Will apply that.

Best regards,
John Jiang