Support shift operators

[cometkim]

As following task of #7057

JS-like shift operators need to be implemented as unified operators

• Left shift (<<, lsl) - support int, bigint
• Right shift (>>, asr) - support int, bigint
• Unsigned right shift (>>>, lsr) - support int

Old names should be kept for compatibility, but introducing longer clear names would be good. e.g. leftShift, unsignedRightShift

>>> only accepts int, but is a unified operator for consistency.

This adds new token rules to the syntax, follow-up tasks for editor support will be opened.

[cometkim]

Assigned to @gwansikk