[CFE] Inline Class const constructors requires const-functions experiment

[ds84182]

Repro:

inline class Vec2D {
  final (double, double) xy;
  const Vec2D(double x, double y) : xy = (x, y);

  static const zero = Vec2D(0.0, 0.0);
}

Passes in analyzer, errors in CFE as it is transformed into a static method & static invocations are not allowed in const fns. Ideally it should ignore this for members declared isConst as they can't be declared const in user code without the experiment enabled.

The error can't be circumvented in either Analyzer or CFE via (0.0, 0.0) as Vec2D.

[bwilkerson]

The analyzer does not yet support inline classes and there is no target data for when support will be added. I'm going to remove the analyzer tag in favor of the general tracking issue at #49732.