Auto merge of #24789 - gterzian:fix_unloading, r=jdm

Fix unloading, active BC, and clearing js runtime

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Do not set the window to be the currently active one for the windowproxy as part of `load`, as it will be done later when the document activity is set. And doing it later means that when unload runs, it is with the unloaded pipeline as the active window.

Only nullify the window proxy if it's not used by another (currently-active) window.

---
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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #24591 (GitHub issue number if applicable)

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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1 files changed, 0 insertions, 1 deletions

diff --git a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/083.html.ini b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/083.html.ini
index 242251f7104..9272fa0716d 100644
--- a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/083.html.ini
+++ b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/083.html.ini
@@ -1,6 +1,5 @@
 [083.html]
   type: testharness
-  expected: ERROR
   [ scheduler: event listener defined by script in a document in history]
     expected: FAIL