requires.extraPropDefns.vmOpts doesn't need -Xbootclasspath/a:bootClasses

to make sure that classes listed in `requires.extraPropDefns.bootlibs` are in BCP, jtreg automatically adds corresponding `-Xbootclasspath/a:` to the options list, so `requires.extraPropDefns.vmOpts` doesn't have to have `-Xbootclasspath/a:bootClasses`