fix utf8 handling when importing json

[snoglobe]

What does this PR do?

this closes #10851 - when importing JSON files, strings were encoded as utf8 which caused problems when evaluated in js core

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• Code changes

How did you verify your code works?

[robobun]

❌ @snoglobe, your commit 991f3c2 has 8 failures in #3933:

test/js/node/watch/fs.watch.test.ts - timeout on 🍎 14 x64

test/js/web/streams/streams.test.js - 1 failing on 🍎 13 x64

test/js/web/streams/streams.test.js - 1 failing on 🍎 14 x64

test/js/node/test/parallel/child-process-exec-timeout-kill.test.js - 1 failing on 🍎 14 aarch64

test/js/web/fetch/fetch-tcp-stress.test.ts - timeout on 🍎 13 aarch64

test/js/web/fetch/fetch-tcp-stress.test.ts - timeout on 🍎 14 x64

test/js/web/timers/setInterval.test.js - 1 failing on 🪟 x64-baseline

test/cli/watch/watch.test.ts - 2 failing on 🪟 x64

test/cli/watch/watch.test.ts - 2 failing on 🪟 x64-baseline

test/cli/hot/watch.test.ts - 1 failing on 🪟 x64

test/cli/hot/watch.test.ts - 1 failing on 🪟 x64-baseline

test/cli/install/bun-link.test.ts - 1 failing on 🪟 x64

[paperdave]

im realizing an existing problem with this code, which is that there are 5 or so of these JSON parse functions which are all identical but have slightly different things. the perfect world makes this one single function, which can be configured as needed.

but that has no runtime difference, and neither does this. lgtm

[dylan-conway]

im realizing an existing problem with this code, which is that there are 5 or so of these JSON parse functions which are all identical but have slightly different things. the perfect world makes this one single function, which can be configured as needed.

I agree, json_parser.zig needs a cleanup