RFR(XS): 8202282: [TESTBUG] appcds TestCommon.makeCommandLineForAppCDS() can be removed

[Calvin Cheung]

bug: https://bugs.openjdk.java.net/browse/JDK-8202282

webrev: http://cr.openjdk.java.net/~ccheung/8202282/webrev.00/

A small fix to remove the unnecessary makeCommandLineForAppCDS() method 
and its usage.

Testing:
     hs-tier1,2,3
     Manually ran the graal test on linux-x64 with the 
-XX:+UnlockExperimentalVMOptions -XX:+UseJVMCICompiler options.

thanks,
Calvin