Failing forc unit test: ok_vec_buffer_ownership

[sdankel]

With the test uncommented, forc test --path sway-lib-std results in this error:

Verification failed at ok_vec_buffer_ownership::entry
library {
    entry fn ok_vec_buffer_ownership() -> (), !4 {
        local [u8; 4] __anon_0
        local { u64, ( () | u8 ) } __anon_1
        local { u64, ( () | u8 ) } __anon_2
        local mut { { u64, u64 }, u64 } bytes
        local mut { { u64, u64 }, u64 } bytes_
error: Internal compiler error: Verification failed: Struct field type mismatch: (Element type "u64" versus index type Some("u8")).
Please file an issue on the repository and include the code that triggered this error.

It also fails for ok_bytes_buffer_ownership

When fixed, we should uncomment the tests. Thanks @alfiedotwtf for discovering these

[sdankel]

@bitzoic @IGI-111 for viz

These tests weren't failing in CI due to #6566

[sdankel]

It looks like this is the first instance they failed on master: https://github.com/FuelLabs/sway/actions/runs/10812086601/job/29992938006

From this PR: #6526

cc @xunilrj

[sdankel]

Confirmed that changing this section of code back fixes the compiler error. I'm not sure if this is the best fix though. Thoughts?