Currently when we construct an WhereMatchExpression we instantiate a JsFunction object, which is a wrapper encapsulating common logic for running JS code in $where expression.

When we translate this expression into an SBE plan, we make a copy of this JsFunction object, which is an expensive operation, since we re-parse and re-compile the JS function from scratch. Instead, we should reuse the original object stored in WhereMatchExpression since this expression will never need it again once translated into SBE.