Remove support for multiple children for imaxminSimplifier

Replace 'num_children' with '2' in 'imaxminSimplifier()'
Fixes eclipse-omr#4176

Signed-off-by: Aidan Ha <qbha@edu.uwaterloo.ca>

compiler/optimizer/OMRSimplifierHandlers.cpp

@@ -16947,7 +16947,6 @@ TR::Node *imaxminSimplifier(TR::Node * node, TR::Block * block, TR::Simplifier *
    simplifyChildren(node, block, s);
 
    int32_t i = 0;
-   int32_t num_children = node->getNumChildren();
    int32_t min = 0, max = 0;
    uint32_t umin = 0, umax = 0;
    bool is_all_const = true;
@@ -16957,7 +16956,7 @@ TR::Node *imaxminSimplifier(TR::Node * node, TR::Block * block, TR::Simplifier *
    bool max_opcode = node->getOpCodeValue() == TR::imax || node->getOpCodeValue() == TR::iumax;
    TR::Node * constNode = NULL;
 
-   for (i = 0; i < num_children; i++)
+   for (i = 0; i < 2; i++)
       {
       if (is_signed && node->getChild(i)->getOpCode().isLoadConst())
          {
@@ -16977,7 +16976,7 @@ TR::Node *imaxminSimplifier(TR::Node * node, TR::Block * block, TR::Simplifier *
 
    if (has_const)
       {
-      for (i = 0; i < num_children; i++)
+      for (i = 0; i < 2; i++)
          {
          if (is_signed && node->getChild(i)->getOpCode().isLoadConst())
             {