Simplify in-memory representation of JsDocInfo.
Simplify in-memory representation of JsDocInfo.

This change removes the overhead of maintaining an `ImmutableList` for each `JsDocInfo`.

PiperOrigin-RevId: 446085558

google/closure-compiler,ChadKillingsworth/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,google/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,nawawi/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,ChadKillingsworth/closure-compiler,nawawi/closure-compiler,google/closure-compiler,google/closure-compiler