Seriously, the absence of a published standard from a credible and relevant standards body would be my primary objection to the phrase. Barring that, de facto standardization would be indicated by multiple interoperable implementations from more than one vendor and widespread adoption. LLVM IR and PNaCl are, at best, documented. That's better than undocumented, but it's a long way from standardized.

I never said asm.js is standardized. ECMA/JavaScript is, though, and asm.js is just a well-defined conventional subset of JS. There doesn't need to be a standard.