[wasm] Remove the print(returnval) and use it to fail shaper

docs/wasm-shaper.md

@@ -68,7 +68,6 @@ And now we can run it!
 
 ```
 % hb-shape test-wasm.ttf abc --shapers=wasm
-1
 [cent=0|sterling=1|fraction=2]
 ```
 
@@ -114,6 +113,5 @@ With this compiled into a WASM module, and installed into our font again, finall
 ```
 $ hb-shape test-wasm.ttf abc
 Hello from Rust!
-1
 [cent=0|sterling=1|fraction=2]
 ```

src/hb-wasm-shape.cc

@@ -213,13 +213,7 @@ _hb_wasm_shape (hb_shape_plan_t    *shape_plan,
     goto fail;
   }
 
-  printf ("%i\n", results[0].of.i32);
-
-
-  if (!face_data)
-    goto fail;
-
-  if (0)
+  if (!results[0].of.i32)
   {
 fail:
     ret = false;