Run the With hooks around WithRuntimeDecorator::createArrayBuffer (#58935)

[lavenzg]

Summary:

WithRuntimeDecorator wraps every override in Around around{with_}; except createArrayBuffer(std::shared_ptr<MutableBuffer>), which calls RD::createArrayBuffer directly. It has been like that since external ArrayBuffers were added in facebook/hermes#793, where the overrides next to it did get the guard. HermesRuntimeImpl::createArrayBuffer allocates a JSArrayBuffer on the GC heap, so on makeThreadSafeHermesRuntime it runs without the runtime lock, and reentrancy checks built on WithRuntimeDecorator never see the call.

#45042 and #45049 fixed the same kind of gap for methods that had no WithRuntimeDecorator override at all. This one has an override that just skips the guard, so it wasn't caught there.

A small stress program shows the race: one thread runs an allocating JS loop on a thread-safe runtime while another creates external ArrayBuffers. In a Debug build it fails the makeA() calls can not be interleaved assert in HadesGC. With the guard it runs clean. I didn't add it as a test because it depends on timing. React Native's copy of decorator.h has the same line.

X-link: facebook/hermes#2204

Test Plan:
Added HermesRuntimeDecoratorTest.CreateArrayBufferCallsWith. It wraps makeHermesRuntime() in a counting WithRuntimeDecorator, creates an ArrayBuffer from a MutableBuffer, and checks that before() and after() each ran once. Without the change both counts are 0 and the test fails. With it the test passes, and so does the full APITests binary (356 tests) in a Debug + ASan build.

🤖 Generated with Claude Code

Reviewed By: avp

Differential Revision: D123939407

Pulled By: lavenzg

[meta-codesync]

@lavenzg has exported this pull request. If you are a Meta employee, you can view the originating Diff in D123939407.