8055111: [TESTBUG] jdk.testlibrary.Utils.removeGcOpts doesn't remove -Xconcgc
Reviewed-by: jmasa, brutisso, sla
<test/script/basic/JDK-8012164.js>.error(test/script/basic/JDK-8012164.js:38)
<test/script/basic/JDK-8012164.js>.func(test/script/basic/JDK-8012164.js:33)
<test/script/basic/JDK-8012164.js>.<program>(test/script/basic/JDK-8012164.js:47)