Pyroscope Ad Hoc comparison view should work like Diff flamegraph view

#### Is your feature request related to a problem? Please describe.

I'm frustrated when using the ad hoc comparison view as it shows the profiles side by side instead of overlapped. This makes comparing flamegraphs from different environments difficult.

#### Describe the solution you'd like

I feel like it would make sense to use the same view that diff flamegraph provides, showing a time window over the profiles and overlapping them so you can see what has been added/removed.

#### Describe alternatives you've considered

I can't really think of alternatives but I am open to other solutions that would satisfy this case as its more frustrating using the comparison view than the diff flamegraph view