[wasm] Implemented F32Trunc as a turbofan graph based on int32 instructions.

src/compiler/wasm-compiler.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_COMPILER_WASM_COMPILER_H_
 #define V8_COMPILER_WASM_COMPILER_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/wasm/wasm-opcodes.h"
@@ skipping 158 matching lines @@
   Node* BuildF64Min(Node* left, Node* right);
   Node* BuildF64Max(Node* left, Node* right);
   Node* BuildI32SConvertF32(Node* input);
   Node* BuildI32SConvertF64(Node* input);
   Node* BuildI32UConvertF32(Node* input);
   Node* BuildI32UConvertF64(Node* input);
   Node* BuildI32Ctz(Node* input);
   Node* BuildI32Popcnt(Node* input);
   Node* BuildI64Ctz(Node* input);
   Node* BuildI64Popcnt(Node* input);
+  Node* BuildF32Trunc(Node* input);
 
   Node** Realloc(Node** buffer, size_t count) {
     Node** buf = Buffer(count);
     if (buf != buffer) memcpy(buf, buffer, count * sizeof(Node*));
     return buf;
   }
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_WASM_COMPILER_H_