* core/vm/runtime/tests: add more benchmarks

* core/vm: initial work on improving alloc count for calls to precompiles

name                                  old time/op    new time/op    delta
SimpleLoop/identity-precompile-10M-6     117ms ±75%      43ms ± 1%  -63.09%  (p=0.008 n=5+5)
SimpleLoop/loop-10M-6                   79.6ms ± 4%    70.5ms ± 1%  -11.42%  (p=0.008 n=5+5)

name                                  old alloc/op   new alloc/op   delta
SimpleLoop/identity-precompile-10M-6    24.4MB ± 0%     4.9MB ± 0%  -79.94%  (p=0.008 n=5+5)
SimpleLoop/loop-10M-6                   13.2kB ± 0%    13.2kB ± 0%     ~     (p=0.357 n=5+5)

name                                  old allocs/op  new allocs/op  delta
SimpleLoop/identity-precompile-10M-6      382k ± 0%      153k ± 0%  -59.99%  (p=0.000 n=5+4)
SimpleLoop/loop-10M-6                     40.0 ± 0%      40.0 ± 0%     ~     (all equal)

* core/vm: don't allocate big.int for touch

name                                  old time/op    new time/op    delta
SimpleLoop/identity-precompile-10M-6    43.3ms ± 1%    42.4ms ± 7%     ~     (p=0.151 n=5+5)
SimpleLoop/loop-10M-6                   70.5ms ± 1%    76.7ms ± 1%   +8.67%  (p=0.008 n=5+5)

name                                  old alloc/op   new alloc/op   delta
SimpleLoop/identity-precompile-10M-6    4.90MB ± 0%    2.46MB ± 0%  -49.83%  (p=0.008 n=5+5)
SimpleLoop/loop-10M-6                   13.2kB ± 0%    13.2kB ± 1%     ~     (p=0.571 n=5+5)

name                                  old allocs/op  new allocs/op  delta
SimpleLoop/identity-precompile-10M-6      153k ± 0%       76k ± 0%  -49.98%  (p=0.029 n=4+4)
SimpleLoop/loop-10M-6                     40.0 ± 0%      40.0 ± 0%     ~     (all equal)

* core/vm: reduce allocs in staticcall

name                                  old time/op    new time/op    delta
SimpleLoop/identity-precompile-10M-6    42.4ms ± 7%    37.5ms ± 6%  -11.68%  (p=0.008 n=5+5)
SimpleLoop/loop-10M-6                   76.7ms ± 1%    69.1ms ± 1%   -9.82%  (p=0.008 n=5+5)

name                                  old alloc/op   new alloc/op   delta
SimpleLoop/identity-precompile-10M-6    2.46MB ± 0%    0.02MB ± 0%  -99.35%  (p=0.008 n=5+5)
SimpleLoop/loop-10M-6                   13.2kB ± 1%    13.2kB ± 0%     ~     (p=0.143 n=5+5)

name                                  old allocs/op  new allocs/op  delta
SimpleLoop/identity-precompile-10M-6     76.4k ± 0%      0.1k ± 0%     ~     (p=0.079 n=4+5)
SimpleLoop/loop-10M-6                     40.0 ± 0%      40.0 ± 0%     ~     (all equal)

* trie: better use of hasher keccakState

* core/state/statedb: reduce allocations in getDeletedStateObject

* core/vm: reduce allocations in all call derivates

* core/vm: reduce allocations in call variants

- Make returnstack `uint32`
- Use a `sync.Pool` of `stack`s

* core/vm: fix tests

* core/vm: goimports

* core/vm: tracer fix + staticcall gas fix

* core/vm: add back snapshot to staticcall

* core/vm: review concerns + make returnstack pooled + enable returndata in traces

* core/vm: fix some test tracer method signatures

* core/vm: run gencodec, minor comment polish
Co-authored-by: Péter Szilágyi <peterke@gmail.com>