chore(v8bridge) minor fixes for v8bridge build

[hishamhm]

These need to be fixed in order to produce a bump to ngx_wasm_runtimes.

This puts us in an almost chicken-and-egg situation when bumping V8. We need to make a 3 (or rather 4) step process for bumping V8 if their build process changes:

1. make the tweaks in ngx_wasm_module
2. start an ARM VM and build the ARM binary image
3. bump in ngx_wasm_runtimes
4. bump the CI in ngx_wasm_module

This time I've done things out-of-order by tweaking the repo by hand in the ARM VM to get step 2 done first, but then I realized that step 3 won't work without step 1 (this PR). Another PR with step 4 will then follow.

(Perhaps the build part of util/runtimes/v8.sh should instead live in ngx_wasm_runtimes, so that all steps for building a new V8 artifact lived there, and then ngx_wasm_module could just treat ngx_wasm_runtimes as its V8 upstream, and in its own util/runtimes/v8.sh, if a build from source is desired, it could fetch that repo and run make on it.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.86064%. Comparing base (d834bb0) to head (8151559).
Report is 2 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main        #633         +/-   ##
===================================================
+ Coverage   90.84288%   90.86064%   +0.01776%     
===================================================
  Files             52          52                 
  Lines          11259       11259                 
===================================================
+ Hits           10228       10230          +2     
+ Misses          1031        1029          -2     

see 1 file with indirect coverage changes

Flag	Coverage Δ
unit	90.60539% <ø> (ø)
valgrind	82.53782% <ø> (+0.08783%)	⬆️

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