[package:js] Clean up boolean logic for isJSInteropMember
[package:js] Clean up boolean logic for isJSInteropMember

Change-Id: I364d8029f134e549e6649439e9038a34e486137c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/171630
Reviewed-by: Riley Porter <1b4d70a146dadc0b64cc886a93a8a324abb72aeb@google.com>
Reviewed-by: Srujan Gaddam <4175f2f2dd3cde6c8ffb10fc9674dc09abf813fe@google.com>
Commit-Queue: Riley Porter <1b4d70a146dadc0b64cc886a93a8a324abb72aeb@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk