[wasm][asm.js] Check that property keys are literals for imports.

src/asmjs/asm-typer.cc

Index: src/asmjs/asm-typer.cc
diff --git a/src/asmjs/asm-typer.cc b/src/asmjs/asm-typer.cc
index 85d18269aac5cdfbadff98ef4d93f132487183f6..0ac40ec6f7ad73d0c30bc6ded3ba706e43a071dd 100644
--- a/src/asmjs/asm-typer.cc
+++ b/src/asmjs/asm-typer.cc
@@ -335,6 +335,9 @@ void AsmTyper::InitializeStdlib() {
 AsmTyper::VariableInfo* AsmTyper::ImportLookup(Property* import) {
   auto* obj = import->obj();
   auto* key = import->key()->AsLiteral();
+  if (key == nullptr) {
+    return nullptr;
+  }
 
   ObjectTypeMap* stdlib = &stdlib_types_;
   if (auto* obj_as_property = obj->AsProperty()) {