## Why this should be merged
Registration of extras requires runtime enforcement of payload types. In
production, only a single set of types can be registered and any
attempts at re-registration will panic (by design). Although this makes
production usage safe, it doesn't allow downstream consumers (e.g. data
indexers) to use extras from different chains (e.g. `coreth` _and_
`subnet-evm`) at the same time.
## How this works
1. The `libevm/register.AtMostOnce` type can now be overridden
temporarily.
2. `params`, `core/types`, `core/vm`, and `state` packages introduce
`WithTempRegisteredExtras()` functions.
3. `libevm/temporary.WithRegisteredExtras()` provides "atomic" override
of all extras.
In all cases, the scope of the override is limited to the life of a
single function call.
## How this was tested
Relative to numbered list above:
1. Unit test of new and existing functionality.
2. Integration tests of both packages, demonstrating both payload and
behavioural override.
## Why this should be merged
Importing some `avalanchego` test fixtures automatically imports
`coreth` packages that register extras, which affects testing of other
VMs that depend on `libevm`. All other registered extras can be cleared
with the pattern in this PR.
## How this works
Uses the `register.AtMostOnce` type already used in `params` and
`types`. I forgot to update the `vm` package when implementing the type.
## How this was tested
Existing unit tests.
* feat: override `vm.NewEVM()` args
* test: `vm.Hooks.OverrideNewEVMArgs`
* refactor: use `NewEVMArgs struct` in hook
* chore: `gci`
* fix: clear `vm.Hooks` at end of test
