Move Value from wasmi_core to wasmi crate

[Robbepop]

This is required for the implementation of the reference-types Wasm proposal since (according to the Wasmtime API) it adds two new variants to the Value type, which are:

enum Value {
    FuncRef(Option<Func>),
    ExternRef(Option<ExternRef>),
}

Since Func resides in wasmi we need to pull the Value type into the wasmi crate.

[paritytech-cicd-pr]

BENCHMARKS

	NATIVE			WASMTIME
BENCHMARK	MASTER	PR	DIFF	MASTER	PR	DIFF	WASMTIME OVERHEAD
execute/ bare_call_0	1.34ms	1.34ms	⚪ -0.21%	1.10ms	1.15ms	🔴 4.60%	🟢 -14%
execute/ bare_call_0/typed	1.02ms	1.02ms	⚪ 0.01%	748.93µs	743.77µs	⚪ -0.92%	🟢 -27%
execute/ bare_call_1	1.41ms	1.41ms	🟢 0.11%	1.26ms	1.33ms	🔴 4.61%	🟢 -6%
execute/ bare_call_16	2.43ms	2.25ms	🟢 -7.50%	4.22ms	4.24ms	🔴 0.34%	🟡 88%
execute/ bare_call_16/typed	1.95ms	1.84ms	🟢 -5.48%	2.65ms	2.69ms	🔴 1.67%	🟢 46%
execute/ bare_call_1/typed	1.13ms	1.12ms	⚪ -0.13%	1.11ms	1.09ms	⚪ -0.03%	🟢 -3%
execute/ bare_call_4	1.82ms	1.55ms	🟢 -14.38%	1.89ms	1.92ms	🔴 1.49%	🟢 24%
execute/ bare_call_4/typed	1.14ms	1.13ms	⚪ -0.77%	1.22ms	1.27ms	🔴 3.76%	🟢 12%
execute/ br_table	1.22ms	1.21ms	⚪ 1.41%	1.35ms	1.36ms	⚪ 0.19%	🟢 12%
execute/ count_until	681.94µs	651.11µs	🟢 -4.54%	2.09ms	2.15ms	🔴 2.56%	🔴 230%
execute/ factorial_iterative	318.39µs	318.26µs	⚪ -0.08%	918.36µs	908.69µs	⚪ -1.17%	🔴 186%
execute/ factorial_recursive	627.92µs	670.20µs	🔴 6.65%	1.31ms	1.34ms	🔴 2.60%	🔴 101%
execute/ fib_iterative	1.41ms	1.41ms	⚪ -0.19%	5.04ms	5.05ms	⚪ 0.34%	🔴 259%
execute/ fib_recursive	5.85ms	5.70ms	🟢 -2.45%	11.60ms	11.68ms	⚪ 0.65%	🔴 105%
execute/ global_bump	1.06ms	1.04ms	🟢 -2.31%	2.78ms	2.78ms	⚪ 0.09%	🔴 167%
execute/ global_const	686.89µs	769.63µs	🔴 12.00%	2.12ms	2.30ms	🔴 9.11%	🔴 198%
execute/ host_calls	25.83µs	25.78µs	⚪ 0.37%	37.00µs	36.67µs	⚪ -0.91%	🟢 42%
execute/ memory_fill	1.24ms	1.20ms	🟢 -3.88%	4.09ms	4.08ms	⚪ 0.22%	🔴 241%
execute/ memory_sum	1.24ms	1.19ms	🟢 -3.56%	3.93ms	3.93ms	⚪ 0.04%	🔴 230%
execute/ memory_vec_add	2.46ms	2.37ms	🟢 -3.41%	7.87ms	7.88ms	⚪ -0.08%	🔴 232%
execute/ recursive_is_even	1.16ms	1.13ms	🟢 -3.35%	2.18ms	2.17ms	⚪ -0.62%	🟡 92%
execute/ recursive_ok	153.05µs	144.30µs	🟢 -5.76%	300.88µs	302.54µs	⚪ 0.00%	🔴 110%
execute/ recursive_scan	186.65µs	180.20µs	🟢 -3.33%	389.52µs	391.91µs	⚪ 0.57%	🔴 117%
execute/ recursive_trap	14.08µs	14.71µs	🔴 4.52%	29.34µs	30.63µs	🔴 4.32%	🔴 108%
execute/ regex_redux	526.09µs	528.31µs	⚪ 0.41%	1.41ms	1.41ms	⚪ 0.23%	🔴 167%
execute/ rev_complement	474.62µs	468.53µs	⚪ -1.19%	1.43ms	1.43ms	⚪ -0.01%	🔴 205%
execute/ tiny_keccak	332.73µs	337.53µs	🔴 1.55%	1.17ms	1.17ms	⚪ -0.31%	🔴 245%
execute/ trunc_f2i	700.84µs	704.92µs	⚪ 0.57%	2.19ms	2.18ms	⚪ -0.57%	🔴 209%
instantiate/ wasm_kernel	63.75µs	64.64µs	⚪ 0.87%	82.41µs	84.62µs	⚪ 1.66%	🟢 31%
translate/ erc1155	206.92µs	207.13µs	⚪ 0.18%	378.64µs	393.22µs	🔴 3.85%	🟡 90%
translate/ erc20	101.93µs	100.81µs	⚪ -0.98%	183.81µs	191.45µs	🔴 4.16%	🟡 90%
translate/ erc721	145.11µs	144.72µs	⚪ -0.32%	268.25µs	276.90µs	🔴 3.24%	🟡 91%
translate/ spidermonkey	0.00ns	0.00ns	⚪ 0.71%	0.00ns	0.00ns	🔴 2.84%	🟢 0%
translate/ wasm_kernel	3.80ms	3.83ms	⚪ 0.46%	7.15ms	7.36ms	🔴 2.68%	🟡 92%

Link to pipeline

[codecov-commenter]

Codecov Report

Merging #636 (14f4254) into master (5f9d81a) will decrease coverage by 0.02%.
The diff coverage is 38.88%.

@@            Coverage Diff             @@
##           master     #636      +/-   ##
==========================================
- Coverage   78.50%   78.48%   -0.02%     
==========================================
  Files          85       86       +1     
  Lines        7270     7270              
==========================================
- Hits         5707     5706       -1     
- Misses       1563     1564       +1     

Impacted Files	Coverage Δ
crates/cli/src/main.rs	0.00% <ø> (ø)
crates/core/src/untyped.rs	97.21% <ø> (-0.09%)	⬇️
crates/core/src/value.rs	74.74% <ø> (+12.42%)	⬆️
crates/wasmi/src/engine/func_builder/mod.rs	86.40% <ø> (ø)
crates/wasmi/src/engine/resumable.rs	81.13% <ø> (ø)
crates/wasmi/src/engine/traits.rs	80.00% <ø> (ø)
crates/wasmi/src/func/mod.rs	77.52% <ø> (ø)
crates/wasmi/src/func_type.rs	96.61% <ø> (ø)
crates/wasmi/src/global.rs	46.75% <ø> (ø)
crates/wasmi/src/module/init_expr.rs	45.61% <ø> (ø)
... and 7 more

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