script: LoadBlocker's drop impl shouldn't run after termination. (#36508)

The logic in LoadBlocker::terminate was modified in #34122 to `clone`
the LoadBlocker's inner `load` member instead of `take`ing it. However,
this member serves as a flag so that `LoadBlocker`'s Drop impl can avoid
calling `doc.finish_load` on already terminated loads. The change
results in
unnecessary 'unknown completed load' warnings when Servo is run with
logging enabled.

Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>

Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>

tests/wpt/meta/dom/ranges/Range-cloneContents.html.ini

@@ -0,0 +1,3 @@
+[Range-cloneContents.html]
+  bug: https://github.com/servo/servo/issues/36561
+  expected: ERROR

tests/wpt/meta/dom/ranges/Range-deleteContents.html.ini

@@ -0,0 +1,3 @@
+[Range-deleteContents.html]
+  bug: https://github.com/servo/servo/issues/36561
+  expected: ERROR

tests/wpt/meta/dom/ranges/Range-extractContents.html.ini

@@ -0,0 +1,3 @@
+[Range-extractContents.html]
+  bug: https://github.com/servo/servo/issues/36561
+  expected: ERROR

tests/wpt/meta/dom/ranges/Range-insertNode.html.ini

@@ -0,0 +1,3 @@
+[Range-insertNode.html]
+  bug: https://github.com/servo/servo/issues/36561
+  expected: ERROR

tests/wpt/meta/dom/ranges/Range-surroundContents.html.ini

@@ -0,0 +1,3 @@
+[Range-surroundContents.html]
+  bug: https://github.com/servo/servo/issues/36561
+  expected: ERROR

tests/wpt/meta/mimesniff/media/media-sniff.window.js.ini

@@ -0,0 +1,3 @@
+[media-sniff.window.html]
+  bug: https://github.com/servo/servo/issues/36626
+  expected: TIMEOUT