test: support odd value for kStringMaxLength

[targos]

V8 6.2 will support a larger maximum string length on 64-bit platforms.
Update the test to take into account its odd value ((1 << 30) - 1 - 24).

Refs: v8/v8@e8c9649
Example failing test on canary: https://ci.nodejs.org/job/node-test-commit-linux/11406/nodes=centos7-64/console

@nodejs/v8

Checklist

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

Affected core subsystem(s)

buffer, V8

[jasnell]

CI: https://ci.nodejs.org/job/node-test-pull-request/9376/

[trevnorris]

While I'm looking at this, and in hopes of removing unnecessary tests, this test uses toString('utf16le') and test-stringbytes-external-at-max.js uses toString('latin1'). Both of these will copy the data and turn them an externalized strings. Because they are externalized strings, do they suffer the same limitations as strings that are copied into the heap that need to be tested?

Also, I'm worried that this test now requires allocating 2GB memory. Could we possibly move this test to only run on test-ci, or some such? I've had these tests hang for a while because, while there is enough free memory reported, the kernel is busy moving things into swap because there isn't enough contiguous memory to make the allocation.

[targos]

New CI: https://ci.nodejs.org/job/node-test-pull-request/9460/

@trevnorris do you agree to land this and move your concern to a new issue? This test will not allocate 2GB memory until we upgrade to V8 6.2 (in October).

[jasnell]

One failure is CI is unrelated to this PR

[targos]

Landed in 753b68f

[trevnorris]

@targos As long as we remember to change the test in October that's cool.

[gibfahn]

@trevnorris @targos we could add this concern (as a new issue) to the 9.0.0 milestone, as that's also happening in October. IDK if that's a good idea though.

[saqirltu]

New CI: https://ci.nodejs.org/job/node-test-pull-request/9460/

@trevnorris do you agree to land this and move your concern to a new issue? This test will not allocate 2GB memory until we upgrade to V8 6.2 (in October).

Hi, is it really possible to do this? Hereby from 2019 still not being able to try it yet. Could you please check out my thread? Thanks!
https://npm.community/t/cannot-create-a-string-longer-than-0x3fffffe7-characters/10738