Bug 1248625 - Change 'return false' to 'return nullptr' (r=me)

MozReview-Commit-ID: 75AW4GpR8hd

--HG--
extra : rebase_source : 0ed91fc5a13ebcb6c990409df77440844ba84d4e

js/src/asmjs/WasmText.cpp

@@ -3228,7 +3228,7 @@ EncodeModule(WasmAstModule& module)
 
     for (WasmAstFunc* func : module.funcs()) {
         if (!EncodeFunctionSection(e, *func))
-            return false;
+            return nullptr;
     }
 
     if (!EncodeDataSection(e, module))