8077608: [TESTBUG] Enable Hotspot jtreg tests to run in agentvm mode

8180904: Hotspot tests running with -agentvm failing due to classpath
Summary: Add -cp System.getProperty("java.class.path") to ProcessBuilder arguments.
Reviewed-by: sla, gtriantafill

test/Makefile

@@ -262,6 +262,8 @@ endif
 # Default JTREG to run
 JTREG = $(JT_HOME)/bin/jtreg
 
+# Use agent mode
+JTREG_BASIC_OPTIONS += -agentvm
 # Only run automatic tests
 JTREG_BASIC_OPTIONS += -a
 # Report details on all failed or error tests, times too

test/compiler/jsr292/RedefineMethodUsedByMultipleMethodHandles.java

@@ -26,7 +26,7 @@
  * @bug 8042235
  * @summary redefining method used by multiple MethodHandles crashes VM
  * @compile -XDignore.symbol.file RedefineMethodUsedByMultipleMethodHandles.java
- * @run main RedefineMethodUsedByMultipleMethodHandles
+ * @run main/othervm RedefineMethodUsedByMultipleMethodHandles
  */
 
 import java.io.*;

test/testlibrary/com/oracle/java/testlibrary/ProcessTools.java

@@ -152,6 +152,9 @@ public final class ProcessTools {
     args.add(javapath);
     Collections.addAll(args, getPlatformSpecificVMArgs());
 
+    args.add("-cp");
+    args.add(System.getProperty("java.class.path"));
+
     if (addTestVmOptions) {
       String vmopts = System.getProperty("test.vm.opts");
       if (vmopts != null && vmopts.length() > 0) {