[wasm] asm.js: Add asm_wasm variant to test asm.js->wasm pipeline.

tools/testrunner/local/variants.py

Index: tools/testrunner/local/variants.py
diff --git a/tools/testrunner/local/variants.py b/tools/testrunner/local/variants.py
index b224e41d3768fcdaf34c6127f1cc258dc3e0f59d..ea42bf52480522151a0369862be66e3eed8ae6e6 100644
--- a/tools/testrunner/local/variants.py
+++ b/tools/testrunner/local/variants.py
@@ -13,6 +13,7 @@ ALL_VARIANT_FLAGS = {
   "ignition_staging": [["--ignition-staging"]],
   "ignition_turbofan": [["--ignition-staging", "--turbo"]],
   "preparser": [["--min-preparse-length=0"]],
+  "asm_wasm": [["--validate-asm"]],
 }
 
 # FAST_VARIANTS implies no --always-opt.
@@ -25,8 +26,9 @@ FAST_VARIANT_FLAGS = {
   "ignition_staging": [["--ignition-staging"]],
   "ignition_turbofan": [["--ignition-staging", "--turbo"]],
   "preparser": [["--min-preparse-length=0"]],
+  "asm_wasm": [["--validate-asm"]],
 }
 
 ALL_VARIANTS = set(["default", "stress", "turbofan", "turbofan_opt",
                     "nocrankshaft", "ignition", "ignition_staging",
-                    "ignition_turbofan", "preparser"])
+                    "ignition_turbofan", "preparser", "asm_wasm"])