remove more code used to support old Node.js versions

[kvakil]

This removes ~100 lines of code which were used to support old versions of Node.js. Doing this revealed some more places where we are missing postmortem metadata.

This is best reviewed commit-by-commit.

[codecov-commenter]

Codecov Report

Base: 73.54% // Head: 73.50% // Decreases project coverage by -0.03% :warning:

Coverage data is based on head (caf0646) compared to base (d91aa40). Patch coverage: 91.66% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #417 +/- ## ========================================== - Coverage 73.54% 73.50% -0.04% ========================================== Files 34 34 Lines 5072 5009 -63 ========================================== - Hits 3730 3682 -48 + Misses 1342 1327 -15 ``` | [Impacted Files](https://codecov.io/gh/nodejs/llnode/pull/417?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [src/llv8-constants.h](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsdjgtY29uc3RhbnRzLmg=) | `97.14% <ø> (ø)` | | | [src/llv8-inl.h](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsdjgtaW5sLmg=) | `78.04% <ø> (+3.08%)` | :arrow_up: | | [src/llv8.h](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsdjguaA==) | `74.13% <ø> (ø)` | | | [src/printer.cc](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL3ByaW50ZXIuY2M=) | `75.33% <0.00%> (+0.14%)` | :arrow_up: | | [src/llv8-constants.cc](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsdjgtY29uc3RhbnRzLmNj) | `82.01% <100.00%> (-0.75%)` | :arrow_down: | | [src/llscan.cc](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsc2Nhbi5jYw==) | `60.56% <0.00%> (-1.86%)` | :arrow_down: | | [src/llnode\_module.cc](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsbm9kZV9tb2R1bGUuY2M=) | `87.79% <0.00%> (-0.59%)` | :arrow_down: | | [src/llv8.cc](https://codecov.io/gh/nodejs/llnode/pull/417/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-c3JjL2xsdjguY2M=) | `71.63% <0.00%> (+0.13%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None)

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[No9]

@RafaelGSS Would you mind giving this a review when you have a min. It looks good but just want a second opinion given the size of the change.