* eth/tracers: add basic native loader

* eth/tracers: add GetResult to tracer interface

* eth/tracers: add native call tracer

* eth/tracers: fix call tracer json result

* eth/tracers: minor fix

* eth/tracers: fix

* eth/tracers: fix benchTracer

* eth/tracers: test native call tracer

* eth/tracers: fix

* eth/tracers: rm extra make
Co-authored-by: Martin Holst Swende <martin@swende.se>

* eth/tracers: rm extra make

* eth/tracers: make callFrame private

* eth/tracers: clean-up and comments

* eth/tracers: add license

* eth/tracers: rework the model a bit

* eth/tracers: move tracecall tests to subpackage

* cmd/geth: load native tracers

* eth/tracers: minor fix

* eth/tracers: impl stop

* eth/tracers: add native noop tracer

* renamings
Co-authored-by: Martin Holst Swende <martin@swende.se>

* eth/tracers: more renamings

* eth/tracers: make jstracer non-exported, avoid cast

* eth/tracers, core/vm: rename vm.Tracer to vm.EVMLogger for clarity

* eth/tracers: minor comment fix

* eth/tracers/testing: lint nitpicks

* core,eth: cancel evm on nativecalltracer stop

* Revert "core,eth: cancel evm on nativecalltracer stop"

This reverts commit 01bb908790a369c1bb9d3937df9325c6857bf855.

* eth/tracers: linter nits

* eth/tracers: fix output on err
Co-authored-by: Martin Holst Swende <martin@swende.se>