[wasm] Fix minor ternary mistake.

R=clemensh@chromium.org
BUG=

Review-Url: https://chromiumcodereview.appspot.com/2431183005
Cr-Commit-Position: refs/heads/master@{#40438}

src/wasm/wasm-module.cc

@@ -1459,7 +1459,7 @@ class WasmInstanceBuilder {
           TRACE("init [globals+%u] = [globals+%d]\n", global.offset,
                 old_offset);
           size_t size = (global.type == kAstI64 || global.type == kAstF64)
-                            ? size = sizeof(double)
+                            ? sizeof(double)
                             : sizeof(int32_t);
           memcpy(raw_buffer_ptr(globals, new_offset),
                  raw_buffer_ptr(globals, old_offset), size);