Don't call _kill when its not observable

[Jarred-Sumner]

What does this PR do?

Don't call _kill when its not observable. This skips a getter and call into JS until the PropertyCallback is called.

How did you verify your code works?

Existing tests

[robobun]

❌ @Jarred-Sumner, your commit 76f4052 has 10 failures in #7963:

test/js/bun/http/serve.test.ts - 2 failing on 🍎 14 x64

test/js/bun/http/serve.test.ts - 1 failing on 🍎 13 x64

test/cli/install/registry/bun-install-registry.test.ts - timeout on 🐧 24.04 x64

test/v8/v8.test.ts - 22 failing on 🐧 3.20 aarch64

test/v8/v8.test.ts - timeout on 🐧 20.04 aarch64

test/v8/v8.test.ts - 22 failing on 🐧 3.20 x64

test/v8/v8.test.ts - 22 failing on 🐧 3.20 x64-baseline

test/integration/next-pages/test/next-build.test.ts - 1 failing on 🐧 24.04 x64-baseline

test/integration/next-pages/test/next-build.test.ts - 1 failing on 🐧 3.20 x64-baseline

test/js/bun/css/doesnt_crash.test.ts - timeout on 🐧 12 aarch64

test/cli/run/require-cache.test.ts - 1 failing on 🐧 24.04 aarch64

test/cli/run/require-cache.test.ts - 1 failing on 🐧 24.04 x64

test/cli/run/require-cache.test.ts - 1 failing on 🐧 3.20 aarch64

test/cli/run/require-cache.test.ts - 1 failing on 🍎 14 x64

test/cli/run/require-cache.test.ts - 1 failing on 🍎 13 x64

test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 22.04 aarch64

test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 24.04 aarch64

test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 24.04 x64-baseline

test/js/bun/http/serve-body-leak.test.ts - 1 failing on 🪟 2019 x64

test/js/node/watch/fs.watchFile.test.ts - 1 failing on 🪟 2019 x64-baseline

test/integration/next-pages/test/dev-server-ssr-100.test.ts - 1 failing on 🪟 2019 x64

test/integration/next-pages/test/dev-server-ssr-100.test.ts - 1 failing on 🪟 2019 x64-baseline

[Jarred-Sumner]

This needs to apply on the setter and not just Object.defineProperty or the getter.