Implement WASM big-endian support

src/wasm/encoder.h

Index: src/wasm/encoder.h
diff --git a/src/wasm/encoder.h b/src/wasm/encoder.h
index 19fc39703d63ef1f8add9036f4e42b9a001e4a41..ea4dbe0d424ed6637a96fa15a0437790396a2876 100644
--- a/src/wasm/encoder.h
+++ b/src/wasm/encoder.h
@@ -36,25 +36,13 @@ class ZoneBuffer : public ZoneObject {
 
   void write_u16(uint16_t x) {
     EnsureSpace(2);
-#if V8_TARGET_LITTLE_ENDIAN
-    WriteUnalignedUInt16(pos_, x);
-#else
-    pos_[0] = x & 0xff;
-    pos_[1] = (x >> 8) & 0xff;
-#endif
+    WriteLittleEndianValue<uint16_t>(pos_, x);
     pos_ += 2;
   }
 
   void write_u32(uint32_t x) {
     EnsureSpace(4);
-#if V8_TARGET_LITTLE_ENDIAN
-    WriteUnalignedUInt32(pos_, x);
-#else
-    pos_[0] = x & 0xff;
-    pos_[1] = (x >> 8) & 0xff;
-    pos_[2] = (x >> 16) & 0xff;
-    pos_[3] = (x >> 24) & 0xff;
-#endif
+    WriteLittleEndianValue<uint32_t>(pos_, x);
     pos_ += 4;
   }