8010084: Race in runtime/NMT/BaselineWithParameter.java

Summary: Added a waitFor() on the process
Reviewed-by: mgerdin, sla, zgu

test/runtime/NMT/BaselineWithParameter.java

@@ -43,7 +43,7 @@ public class BaselineWithParameter {
 
     // Run 'jcmd <pid> VM.native_memory baseline=false'
     pb.command(new String[] { JDKToolFinder.getJDKTool("jcmd"), pid, "VM.native_memory", "baseline=false"});
-    pb.start();
+    pb.start().waitFor();
 
     // Run 'jcmd <pid> VM.native_memory summary=false'
     pb.command(new String[] { JDKToolFinder.getJDKTool("jcmd"), pid, "VM.native_memory", "summary=false"});