inference: revive `CachedMethodTable` mechanism (#46535)
`CachedMethodTable` was removed within #44240 as we couldn't confirm any
performance improvement then. However it turns out the optimization was
critical in some real world cases (e.g. #46492), so this commit revives
the mechanism with the following tweaks that should make it more effective:
- create method table cache per inference (rather than per local
inference on a function call as on the previous implementation)
- only use cache mechanism for abstract types (since we already cache
lookup result at the next level as for concrete types)
As a result, the following snippet reported at #46492 recovers the
compilation performance:
```julia
using ControlSystems
a_2 = [-5 -3; 2 -9]
C_212 = ss(a_2, [1; 2], [1 0; 0 1], [0; 0])
@time norm(C_212)
```
> on master
```
julia> @time norm(C_212)
364.489044 seconds (724.44 M allocations: 92.524 GiB, 6.01% gc time, 100.00% compilation time)
0.5345224838248489
```
> on this commit
```
julia> @time norm(C_212)
26.539016 seconds (62.09 M allocations: 5.537 GiB, 5.55% gc time, 100.00% compilation time)
0.5345224838248489
```
