Changes [ x **= 2 ] = [] from

[ x **= 2 ] = []
    ^^^
SyntaxError: Unexpected token **=

to:

[ x **= 2 ] = []
  ^^^^^^^

SyntaxError: Invalid destructuring assignment target
Change-Id: I07170d12c151a94a7f99d37dce17197a3aa6f503
Reviewed-on: https://chromium-review.googlesource.com/c/1355140Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57940}