src: remove unused _external getters

[addaleax]

These getters are unused in our source code, untested (apart from a
test checking that the getters themselves do not throw) and are
useless for JS code due to the opaqueness of v8::Externals.

I can’t really imagine addons depending on this, especially as it’s
undocumented and very niche anyway, but I guess there’s no reason
to not consider this semver-major.

@indutny You introduced this in 6e08bb9, do you happen to remember why?

Ref: #13503

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

src/crypto

[indutny]

I introduced them for a use-case in C++ addon that I had at that time. I can't recall what exactly that addon did, but it is practically impossible to fiddle with SSL and SSL_CTX pointers in any other way.

Does having them in core really harm anyone? Should we just document them?

[addaleax]

@indutny Yes, if you think these make sense to keep around I’d really prefer to document them. Otherwise they end up in this weird space between public API and internals, where nobody can even tell whether it’s a supported API or not.

[mscdex]

If they're going to be documented they shouldn't be underscore-prefixed.

[refack]

From a quick look it seems the JS Accessor is just for testing (pre cctest days maybe)?
Will removing the accessors and test with cctest be a reasonable solution?

[addaleax]

@refack No, @indutny just explained what they were introduced for. There is also no test for their functionality, so I really don’t know where you’re getting that from.

[refack]

From I introduced them for a use-case in C++ addon, but I'm probably jumping to conclusions.

[addaleax]

@refack We could probably get an addon test for these together, but I agree with what the others have said here; the current way in which they are exposed is not really meaningful.

[refack]

@refack We could probably get an addon test for these together, but I agree with what the others have said here; the current way in which they are exposed is not really meaningful.

Sounds like an interesting venture. I haven't written a native addon since v0.10 👴