JSC currently implements Array.prototype.includes, but not %TypedArray%.prototype.includes. Spec text: https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.includes
%TypedArray%.prototype.includes was implemented in r203107. test262 coverage: https://test262.report/browse/built-ins/TypedArray/prototype/includes. *** This bug has been marked as a duplicate of bug 159385 ***