[wasm] Exporting i64 globals causes a link error.

test/mjsunit/wasm/wasm-module-builder.js

 // Copyright 2016 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.
 
 // Used for encoding f32 and double constants to bits.
 let __buffer = new ArrayBuffer(8);
 let byte_view = new Int8Array(__buffer);
 let f32_view = new Float32Array(__buffer);
 let f64_view = new Float64Array(__buffer);
 
@@ skipping 341 matching lines @@
           section.emit_u8(global.mutable);
           if ((typeof global.init_index) == "undefined") {
             // Emit a constant initializer.
             switch (global.type) {
             case kWasmI32:
               section.emit_u8(kExprI32Const);
               section.emit_u32v(global.init);
               break;
             case kWasmI64:
               section.emit_u8(kExprI64Const);
-              section.emit_u8(global.init);
+              section.emit_u32v(global.init);
               break;
             case kWasmF32:
               section.emit_u8(kExprF32Const);
               f32_view[0] = global.init;
               section.emit_u8(byte_view[0]);
               section.emit_u8(byte_view[1]);
               section.emit_u8(byte_view[2]);
               section.emit_u8(byte_view[3]);
               break;
             case kWasmF64:
@@ skipping 173 matching lines @@
     }
     return buffer;
   }
 
   instantiate(ffi) {
     let module = new WebAssembly.Module(this.toBuffer());
     let instance = new WebAssembly.Instance(module, ffi);
     return instance;
   }
 }