Repository: angular
Issue: dev-infra / perf: clan-up existing benchpress benchmarks
Labels: area: performance,refactoring,P3

Benchpress benchmarks in the https://github.com/angular/angular/tree/master/modules/benchmarks could use some cleanup as they accumulated a bit of technical debt through incremental changes over time.

Cleanups to consider are listed below.

### Remove "unused" benchmarks

As a rule of thumb we should only have / maintain benchmarks that are run on LL. If we don't track given benchmark's numbers and use those numbers to drive improvements, we should delete such benchmarks.

There are several categories of benchmarks that are not run / tracked on LL and could be considered for deletion:
* ["old" benchmarks](https://github.com/angular/angular/tree/master/modules/benchmarks/src/old) - it doesn't seem like we use them at all so probably only a liability at this point?
* experiments / hand-written code (either failed or ones that were translated into the production code) - those should be deleted:
  * early iv experiments - not needed as iv impl was incomplete and ngIvy impl is quite different
    *  [largetable](https://github.com/angular/angular/tree/master/modules/benchmarks/src/largetable/iv)
    *  [tree](https://github.com/angular/angular/tree/master/modules/benchmarks/src/tree/iv)
  * VE experiments ([hand-written VE code](https://github.com/angular/angular/tree/master/modules/benchmarks/src/tree/ng2_next)) we are removing VE and we don't want to maintain hand-written code;
   * render3 experimental APIs
      * https://github.com/angular/angular/tree/master/modules/benchmarks/src/tree/render3
      * https://github.com/angular/angular/tree/master/modules/benchmarks/src/tree/render3_function
      * https://github.com/angular/angular/tree/master/modules/benchmarks/src/largetable/render3
* ["external" benchmarks](https://github.com/angular/angular/tree/master/modules/benchmarks_external) - for frameworks other than Angular - here we should decide if we want to keep such benchmarks. My understanding is that we are not actively tracking Angular performance over other benchmarks so we should either start tracking or delete: my vote would go to deleting as we haven't updated / used those benchmarks in years... 
* AngularJS benchmarks - given that AngularJS is no longer maintained, I guess we don't need to keep its benchmarks? 
* [benchmarks that would be better off written as a micro-benchmark](https://github.com/angular/angular/tree/master/modules/benchmarks/src/views)
* benchmarks that are _not_ tracked on LL - either start tracking or delete:
   * https://github.com/angular/angular/tree/master/modules/benchmarks/src/class_bindings
   * https://github.com/angular/angular/tree/master/modules/benchmarks/src/largeform

### Re-consider folders structure

Different benchmarks have different folder structure and we need to unify it. Most notable items:
* `ng2` folder in each benchmark should be re-named to `ng` or  just `angular`

### Consistent files structure for each and every benchmark

Files structure within a given benchmark is hard to follow, see: https://github.com/angular/angular/pull/34034#discussion_r351546032

### Documentation updates

Documentation in https://github.com/angular/angular/blob/master/modules/benchmarks/README.md should be updated to reflect all the above changes.