RFR(xs): 8179103: [Testbug] re-enable the runtime/SharedArchiveFile/BootAppendTests.java test

[Calvin Cheung]

Hi,

Please review this simple fix for re-enabling a test case.

bug: https://bugs.openjdk.java.net/browse/JDK-8179103

webrev: http://cr.openjdk.java.net/~ccheung/8179103/webrev.00/

Tested locally on linux-x64.
Running tests on other platforms.

thanks,
Calvin