C: Revert lazy array initialization and restore hb_array_size() usage

[marcoroth]

This pull request reverts #885 which caused memory issues in WebAssembly by always allocating arrays, even when NULL was passed.

The hb_array_size() function safely returns 0 for NULL arrays, eliminating the need for allocating arrays for all AST Nodes. This was causing the "Cannot enlarge memory" errors in WASM builds, as seen in #1016.

This pull request brings back hb_array_size() in places where we previously accessed array->size directly. With that, we don't need to allocate array_init(8) just so we can assume we always have a size.

The problem is, even if we would use array_init(0) it would allocate memory that we are not going to need. So for now, I think it's better to be avoid allocating arrays and use hb_array_size() until we have fully integrated the new array implementation from #782. (/cc @timkaechele).

I also added a hb_narray_size() for API consistency that should help with the future array migration.

Resolves #1016
(Might also resolve #993)

[pkg-pr-new]

npx https://pkg.pr.new/@herb-tools/formatter@1025

npx https://pkg.pr.new/@herb-tools/language-server@1025

npx https://pkg.pr.new/@herb-tools/linter@1025

commit: c4d43e4

[github-actions]

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