[wasm] Support undefined indirect table entries, behind a flag.

src/wasm/wasm-opcodes.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_WASM_OPCODES_H_
 #define V8_WASM_OPCODES_H_
 
 #include "src/machine-type.h"
 #include "src/signature.h"
 
@@ skipping 450 matching lines @@
 
 enum WasmOpcode {
 // Declare expression opcodes.
 #define DECLARE_NAMED_ENUM(name, opcode, sig) kExpr##name = opcode,
   FOREACH_OPCODE(DECLARE_NAMED_ENUM)
 #undef DECLARE_NAMED_ENUM
 };
 
 // The reason for a trap.
 #define FOREACH_WASM_TRAPREASON(V) \
-  V(TrapUnreachable)          \
-  V(TrapMemOutOfBounds)       \
-  V(TrapDivByZero)            \
-  V(TrapDivUnrepresentable)   \
-  V(TrapRemByZero)            \
-  V(TrapFloatUnrepresentable) \
-  V(TrapFuncInvalid)          \
+  V(TrapUnreachable)               \
+  V(TrapMemOutOfBounds)            \
+  V(TrapDivByZero)                 \
+  V(TrapDivUnrepresentable)        \
+  V(TrapRemByZero)                 \
+  V(TrapFloatUnrepresentable)      \
+  V(TrapFuncInvalid)               \
   V(TrapFuncSigMismatch)
 
 enum TrapReason {
 #define DECLARE_ENUM(name) k##name,
   FOREACH_WASM_TRAPREASON(DECLARE_ENUM)
   kTrapCount
 #undef DECLARE_ENUM
 };
 
 // A collection of opcode-related static methods.
@@ skipping 176 matching lines @@
       default:
         return "<unknown>";
     }
   }
 };
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_OPCODES_H_