[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 9f200d121e4fb89c57c3e78fdc597ac3a9059ceb..1166c2fdd1354237bbf430f8d1b9a14ee7ddd9a3 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -1516,6 +1516,10 @@ 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));