Add BUN_DEBUG flag to control where debug logs go (#9019)

* Add `BUN_DEBUG` flag to control where debug logs go

* Update all the actions

* Configure temp

* use spawn instead of rm

* Use CLOSE_RANGE_CLOEXEC

* Make some tests more reproducible

* Update hot.test.ts

* Detect file descriptor leaks and wait for stdout

* Update runner.node.mjs

* Update preload.ts

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Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

bunfig.toml

@@ -6,3 +6,4 @@
 #
 # Instead, we can only scan the test directory for Bun's runtime tests
 root = "test"
+preload = "./test/preload.ts"