Fix - Missing BPF_MUL result sign extension

[Lichtso]

#498 was split into #494, #499 and some commits left for the old multiplication instruction encodings, which were not PRed yet.

[codecov-commenter]

Codecov Report

Merging #518 (6778797) into main (d18d47c) will increase coverage by 0.03%.
Report is 11 commits behind head on main.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #518      +/-   ##
==========================================
+ Coverage   89.60%   89.63%   +0.03%     
==========================================
  Files          23       23              
  Lines       10261    10301      +40     
==========================================
+ Hits         9194     9233      +39     
- Misses       1067     1068       +1     

Files Changed	Coverage Δ
src/jit.rs	92.36% <100.00%> (ø)

... and 4 files with indirect coverage changes