Editorial: Add assertion that generatorKind is not non-generator (#3379)

Author: d01c2

esmeta-ignore.json

@@ -8,6 +8,5 @@
   "GetViewByteLength",
   "INTRINSICS.Atomics.notify",
   "Record[SourceTextModuleRecord].ExecuteModule",
-  "TypedArrayLength",
-  "YieldExpression[2,0].Evaluation"
+  "TypedArrayLength"
 ]

spec.html

@@ -24254,6 +24254,7 @@ <h1>Runtime Semantics: Evaluation</h1>
       <emu-grammar>YieldExpression : `yield` `*` AssignmentExpression</emu-grammar>
       <emu-alg>
         1. Let _generatorKind_ be GetGeneratorKind().
+        1. Assert: _generatorKind_ is either ~sync~ or ~async~.
         1. Let _exprRef_ be ? Evaluation of |AssignmentExpression|.
         1. Let _value_ be ? GetValue(_exprRef_).
         1. Let _iteratorRecord_ be ? GetIterator(_value_, _generatorKind_).