Clear peeking ilgen callNode from callsite

The callNode generated from peeking ilgen is used to create the
callsite of appropriate type and check for targets. Set it to NULL when
both are done so that inliner code can reliably figure out whether the
callsite has been updated with proper ilgen callNode or not.

Signed-off-by: Yi Zhang <yizhang@ca.ibm.com>

Author: Yi Zhang

runtime/compiler/optimizer/J9EstimateCodeSize.cpp

@@ -1239,7 +1239,8 @@ TR_J9EstimateCodeSize::realEstimateCodeSize(TR_CallTarget *calltarget, TR_CallSt
             TR::Node* parent = tt->getNode();
             TR::Node* callNode = tt->getNode()->getFirstChild();
             TR::SymbolReference* symRef =  callNode->getSymbolReference();
-            if (!callNode->getSymbolReference()->isUnresolved() && !visited.contains(callNode))
+            if (!callNode->getSymbolReference()->isUnresolved() && !visited.contains(callNode) &&
+               !callSites[callNode->getByteCodeIndex()]) // skip if the callsite has already been created for this byte code index
                {
                int i = callNode->getByteCodeIndex();
                visited.add(callNode);
@@ -1268,6 +1269,10 @@ TR_J9EstimateCodeSize::realEstimateCodeSize(TR_CallTarget *calltarget, TR_CallSt
                   //support counters
                   calltarget->addDeadCallee(callsite);
                   }
+
+               // clearing the node generated by peeking ilgen
+               // _callNode will be filled with node generated by actual ilgen @see TR_InlinerBase::findAndUpdateCallSiteInGraph
+               callsite->_callNode = NULL;
                }
             }
          }