Fix supportsIntrinsicCaseConversion in ilgen

The call node generated was not cleaned up from the oprand stack when
loading const instead. Besides, the code for handling this recognized
method can be moved up to avoid applying the redundant logic for a
general call.

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

runtime/compiler/ilgen/Walker.cpp

@@ -4643,13 +4643,6 @@ TR_J9ByteCodeIlGenerator::genInvoke(TR::SymbolReference * symRef, TR::Node *indi
 
     */
 
-
-   TR::Node * savedNode = NULL;
-   if (_stack->topIndex() > 0)
-      {
-      savedNode = _stack->element(_stack->topIndex());
-      }
-
 #define DAA_PRINT(a) \
 case a: \
    traceMsg(comp(), "DAA Method found: %s\n", #a); \
@@ -4955,7 +4948,12 @@ break
        return NULL;
        }
 
-    int32_t constToLoad = 0;
+   if (symbol->getRecognizedMethod() == TR::com_ibm_jit_JITHelpers_supportsIntrinsicCaseConversion)
+      {
+      pop(); //pop the receiver since it's not used
+      loadConstant(TR::iconst, cg()->getSupportsInlineStringCaseConversion() ? 1 : 0);
+      return NULL;
+      }
 
    if (!isStatic && _classInfo && !symRef->isUnresolved())
       {
@@ -5064,17 +5062,6 @@ break
          }
       }
 
-   if(symbol->getRecognizedMethod() == TR::com_ibm_jit_JITHelpers_supportsIntrinsicCaseConversion)
-      {
-      if (cg()->getSupportsInlineStringCaseConversion())
-         constToLoad = 1;
-      else
-         constToLoad  = 0; // should already be 0 but just incase..
-
-      loadConstant(TR::iconst, constToLoad);
-      return NULL;
-      }
-
    if (cg()->getSupportsInlineStringCaseConversion() &&
          (symbol->getRecognizedMethod() == TR::com_ibm_jit_JITHelpers_toUpperIntrinsicLatin1 ||
             symbol->getRecognizedMethod() == TR::com_ibm_jit_JITHelpers_toLowerIntrinsicLatin1 ||