BenchmarksRunner does not override jvm args of forked processes. (#12097)

Fixes "PolyglotException: No language of id epb found". Turns out that we have accidentally overridden all the arguments to forked JVMs of JMH to just `-Dbench.all=true`.

Now, `sbt std-benchmarks/bench` works also locally. Before this PR, they also failed locally.

Author: Akirathan

lib/java/benchmarks-common/src/main/java/org/enso/interpreter/bench/BenchmarksRunner.java

@@ -27,7 +27,7 @@ public class BenchmarksRunner {
 
   public static void run(String[] args) throws RunnerException {
     if (args.length == 0) {
-      args = new String[] {"--jvmArgs=-Dbench.all=true"};
+      args = new String[] {"--jvmArgsPrepend=-Dbench.all=true"};
     }
     CommandLineOptions cmdOpts = null;
     try {