[wasm] Introduce the TrapIf and TrapUnless operators to generate trap code.

src/compiler/ia32/instruction-selector-ia32.cc

Index: src/compiler/ia32/instruction-selector-ia32.cc
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc
index bb0be9ac6807ae3de1796ad2b4089e977f146d76..c7060f9e1631667aeecee3327763b5a5654181e0 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -1501,6 +1501,10 @@ void InstructionSelector::VisitDeoptimizeUnless(Node* node) {
   VisitWordCompareZero(this, node, node->InputAt(0), &cont);
 }
 
+void InstructionSelector::VisitTrapIf(Node* node) { UNREACHABLE(); }
+
+void InstructionSelector::VisitTrapUnless(Node* node) { UNREACHABLE(); }
+
 void InstructionSelector::VisitSwitch(Node* node, const SwitchInfo& sw) {
   IA32OperandGenerator g(this);
   InstructionOperand value_operand = g.UseRegister(node->InputAt(0));