Fix missing synchronization in statistics listener.

(cherry picked from commit 273ac16)

Author: chumer

truffle/src/com.oracle.truffle.runtime/src/com/oracle/truffle/runtime/debug/StatisticsListener.java

@@ -190,7 +190,7 @@ public synchronized void onCompilationInvalidated(OptimizedCallTarget target, Ob
     }
 
     @Override
-    public void onCompilationStarted(OptimizedCallTarget target, AbstractCompilationTask task) {
+    public synchronized void onCompilationStarted(OptimizedCallTarget target, AbstractCompilationTask task) {
         compilations++;
         final CurrentCompilationStatistics times = new CurrentCompilationStatistics(task.tier());
         currentCompilationStatistics.set(times);
@@ -291,7 +291,7 @@ public synchronized void onCompilationSuccess(OptimizedCallTarget target, Abstra
     }
 
     @Override
-    public void onCompilationFailed(OptimizedCallTarget target, String reason, boolean bailout, boolean permanentBailout, int tier, Supplier<String> lazyStackTrace) {
+    public synchronized void onCompilationFailed(OptimizedCallTarget target, String reason, boolean bailout, boolean permanentBailout, int tier, Supplier<String> lazyStackTrace) {
         if (bailout) {
             if (permanentBailout) {
                 permanentBailouts++;
@@ -309,7 +309,7 @@ public void onCompilationFailed(OptimizedCallTarget target, String reason, boole
     }
 
     @Override
-    public void onEngineClosed(EngineData runtimeData) {
+    public synchronized void onEngineClosed(EngineData runtimeData) {
         printStatistics(runtimeData);
     }