[wasm] New implementation of popcnt and ctz.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 192d16b64d7ba8613d90b4b4ab7369426c0d7dde..ed904c818fc111993c55616ea10fc9675b90ccda 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -948,6 +948,10 @@ class ExternalReference BASE_EMBEDDED {
   static ExternalReference wasm_int64_mod(Isolate* isolate);
   static ExternalReference wasm_uint64_div(Isolate* isolate);
   static ExternalReference wasm_uint64_mod(Isolate* isolate);
+  static ExternalReference wasm_word32_ctz(Isolate* isolate);
+  static ExternalReference wasm_word64_ctz(Isolate* isolate);
+  static ExternalReference wasm_word32_popcnt(Isolate* isolate);
+  static ExternalReference wasm_word64_popcnt(Isolate* isolate);
 
   static ExternalReference f64_acos_wrapper_function(Isolate* isolate);
   static ExternalReference f64_asin_wrapper_function(Isolate* isolate);