webdriver: Greatly improve execution speed for all tests using SetWindowSize (#37712)

1. Remove the unnecessary new thread which use GetWindowRect command and
blocks for 500ms. Previously this is necessary because constellation
forward "resize" to embedder, and WebDriver wait for a constant
sufficient time to `GetWindowRect` in the new thread. This caused long
delay because there are many subtests and SetWindowRect is called
between each.
2. Remove `resize_timeout`
3. Return current dimension instead of 0 from embedder when it fails to
resize.
4. Do resizing as long as one of width/height is `Some`, according to
spec.

Testing: All Conformance test with new passing cases.
Fixes: https://github.com/servo/servo/pull/37663#issuecomment-2999120615

---------

Signed-off-by: Euclid Ye <yezhizhenjiakang@gmail.com>

tests/wpt/meta/webdriver/tests/classic/set_window_rect/set.py.ini

@@ -29,17 +29,32 @@
   [test_set_to_screen_size]
     expected: FAIL
 
-  [test_set_larger_than_screen_size]
-    expected: FAIL
-
   [test_width_height_floats]
     expected: FAIL
 
-  [test_height_width_as_current]
-    expected: FAIL
-
   [test_height_as_current]
     expected: FAIL
 
   [test_width_as_current]
     expected: FAIL
+
+  [test_no_change[rect12\]]
+    expected: FAIL
+
+  [test_no_change[rect13\]]
+    expected: FAIL
+
+  [test_no_change[rect16\]]
+    expected: FAIL
+
+  [test_no_change[rect17\]]
+    expected: FAIL
+
+  [test_no_change[rect18\]]
+    expected: FAIL
+
+  [test_no_change[rect19\]]
+    expected: FAIL
+
+  [test_set_larger_than_screen_size]
+    expected: FAIL

tests/wpt/meta/webdriver/tests/classic/take_screenshot/iframe.py.ini

@@ -1,9 +0,0 @@
-[iframe.py]
-  [test_always_captures_top_browsing_context]
-    expected: FAIL
-
-  [test_source_origin[same_origin\]]
-    expected: FAIL
-
-  [test_source_origin[cross_origin\]]
-    expected: FAIL