Incorrect handling of calendar names during parsing #682

Temporal.PlainDate.from("2020-01-01[u-ca=gregory-foobar]");
// should raise an error, but returns "2020-01-01[u-ca=gregory]"
Temporal.PlainDate.from("2020-01-01[u-ca=persian-foobar]");
// ditto, "2020-01-01[u-ca=persian-foobar]"
Temporal.PlainDate.from("2020-01-01[u-ca=chinese-foobar]");
// ditto, "2020-01-01[u-ca=chinese]"
Temporal.PlainDate.from({ year: 2020, month: 1, day: 1, calendar: "chinese-foobar" });
// ditto, "2020-01-25[u-ca=chinese]"

// "islamic" calendar is unsupported when a property bag is passed (which is spec-compliant),
// but doesn't raise an error during string parsing
Temporal.PlainDate.from("2020-01-01[u-ca=islamic]");
// "2020-01-01[u-ca=islamic-civil]"
// ditto for "islamic-rgsa"
Temporal.PlainDate.from("2020-01-01[u-ca=islamic-rgsa]");
// "2020-01-01"