Make branch instructions offset program counter by delta (PR)

[Robbepop]

Implements #473.

This PR also introduces the LabelRegistry abstraction that helps build up BranchParams during compilation of a Wasm program lazily. The new LabelRegistry makes it possible to reuse more heap allocated memory than was possible before for some significant speedups in the range of 5-6%.

Merging this PR will allow us to improve and optimize the wasmi bytecode executor instruction pointer.

[paritytech-cicd-pr]

CRITERION BENCHMARKS

BENCHMARK	MASTER	PR	Diff
execute/count_until	2.9869 ms	2.0834 ms	🟢 -30.2877 %
execute/factorial_iterative	1.6852 µs	1.4352 µs	🟢 -14.7267 %
execute/factorial_recursive	2.1872 µs	2.2381 µs	🔴 +2.4623 %
execute/fib_iterative	10.1064 ms	9.4443 ms	🟢 -5.5977 %
execute/fib_recursive	19.3727 ms	20.2258 ms	🔴 +4.0821 %
execute/global_bump	3.8568 ms	3.9011 ms	🔴 +1.1847 %
execute/host_calls	35.1847 µs	35.2119 µs	⚪ +0.0937 %
execute/memory_fill	9.6104 ms	9.464 ms	🟢 -1.5326 %
execute/memory_sum	8.9388 ms	9.1458 ms	🔴 +2.2346 %
execute/memory_vec_add	16.3352 ms	16.0494 ms	🟢 -1.7625 %
execute/recursive_is_even	3.0453 ms	3.4298 ms	🔴 +12.8158 %
execute/recursive_ok	402.6154 µs	405.192 µs	⚪ +0.8194 %
execute/recursive_scan	511.8727 µs	527.8285 µs	🔴 +3.3084 %
execute/recursive_trap	39.5421 µs	38.7193 µs	🟢 -1.9397 %
execute/regex_redux	3.515 ms	3.5176 ms	⚪ +0.1921 %
execute/rev_complement	3.1142 ms	3.1516 ms	🔴 +1.1625 %
execute/tiny_keccak	2.6718 ms	2.6652 ms	⚪ -0.3952 %
execute/trunc_f2i	3.7365 ms	3.7093 ms	⚪ -0.719 %
instantiate/wasm_kernel	78.1051 µs	78.0839 µs	⚪ +0.0345 %
translate/wasm_kernel	6.4006 ms	6.1372 ms	🟢 -4.1014 %

Link to pipeline

[codecov-commenter]

Codecov Report

Merging #478 (b2d609a) into master (5ce1d4f) will increase coverage by 0.08%.
The diff coverage is 86.88%.

@@            Coverage Diff             @@
##           master     #478      +/-   ##
==========================================
+ Coverage   79.15%   79.24%   +0.08%     
==========================================
  Files          73       74       +1     
  Lines        6255     6296      +41     
==========================================
+ Hits         4951     4989      +38     
- Misses       1304     1307       +3     

Impacted Files	Coverage Δ
crates/wasmi/src/engine/bytecode/tests.rs	100.00% <ø> (ø)
crates/wasmi/src/engine/mod.rs	83.49% <ø> (ø)
crates/wasmi/src/engine/func_builder/labels.rs	70.90% <70.90%> (ø)
...ates/wasmi/src/engine/func_builder/inst_builder.rs	78.43% <78.78%> (+4.51%)	⬆️
crates/wasmi/src/engine/bytecode/utils.rs	76.27% <95.45%> (+7.52%)	⬆️
crates/wasmi/src/engine/bytecode/mod.rs	100.00% <100.00%> (ø)
crates/wasmi/src/engine/executor.rs	98.41% <100.00%> (ø)
...tes/wasmi/src/engine/func_builder/control_frame.rs	90.00% <100.00%> (ø)
crates/wasmi/src/engine/func_builder/mod.rs	89.43% <100.00%> (+0.52%)	⬆️
crates/wasmi/src/module/tests.rs	98.66% <100.00%> (ø)

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