buffer: standardize array index check

[trevnorris]

Checklist

• tests and code linting passes
• a test and/or benchmark is included
• the commit message follows commit guidelines

Affected core subsystem(s)

buffer

Description of change

ParseArrayIndex() was requesting a Uint32Value(), but assigning it to an
in32_t. This caused slight differences in error message reported in edge
cases of argument parsing. Fixed by getting the IntegerValue() before
checking if the value is < 0. Added test of API that was affected.

R=@bnoordhuis
R=@jasnell

CI: https://ci.nodejs.org/job/node-test-pull-request/2179/

[jasnell]

LGTM

[trevnorris]

Thanks much! Landed in 9d94cc5.

[MylesBorins]

@trevnorris there are some failing tests on v4.x-staging with this change.

Here's the diff

++<<<<<<< 5faeb7ebf381445bc1a156669f983d6133659310
 +  int32_t tmp_i = arg->Int32Value();
++=======
+   int64_t tmp_i = arg->IntegerValue();
++>>>>>>> buffer: standardize array index check

Perhaps the change isn't necessary since the assigned value and return match up on the v4.x stream

[MylesBorins]

ping @trevnorris should this be backported?

[trevnorris]

@thealphanerd I wouldn't consider this something that's necessary to backport. Especially since it implicitly relies on several other parts working in a specific way.

[MylesBorins]

thanks for the heads up. moving it to don't land.