Getter completion on pattern destructing when specifying types is incorrect

[FMorschel]

After #59854, using the completion after the :s here, with always_specify_types, I was expecting:

abstract class A {
  bool get isEmpty;
}

class B {
  final bool isEmpty;
  B(this.isEmpty);
}

void foo(Object o) {
  if (o case A(:bool isEmpty) || B(:bool isEmpty)) { // Try both locations
    isEmpty;
  }
}

But the first case, being a "method" currently completes after the : as bool Function() isEmpty.

CC @DanTup

[FMorschel]

Here is the CL https://dart-review.googlesource.com/c/sdk/+/456880

[FMorschel]

Friendly ping @srawlins (not that this is here for a long time, but because it is simple)

I've added you as a second reviewer here. It is simply 34 lines so simple to review. Thanks!