Bug 243560

fast/layers/add-layer-with-nested-stacking.html is a constant text failure on iOS

Regression point appears to be 253079@main https://github.com/WebKit/WebKit/commit/fe9010d466486263512b39c1027e5c2186905c58
When attempting to reproduce using run-webkit-tests this test runs successfully at 253078@main but fails at 253079@main 

HISTORY:
https://results.webkit.org/?suite=layout-tests&test=fast%2Flayers%2Fadd-layer-with-nested-stacking.html

DIFF:
--- /Volumes/Data/worker/Apple-iOS-15-Simulator-Release-arm64-WK2-Tests/build/layout-test-results/fast/layers/add-layer-with-nested-stacking-expected.txt
+++ /Volumes/Data/worker/Apple-iOS-15-Simulator-Release-arm64-WK2-Tests/build/layout-test-results/fast/layers/add-layer-with-nested-stacking-actual.txt
@@ -7,5 +7,4 @@
   RenderBlock {DIV} at (0,0) size 784x100
 layer at (8,8) size 100x100
   RenderBlock (generated) at (0,0) size 100x100 [bgcolor=#008000]
-    RenderText at (0,-15) size 0x19
-      text run at (0,-15) width 0: ""
+    RenderText at (0,0) size 0x0

DIFF-URL:
https://build.webkit.org/results/Apple-iOS-15-Simulator-Release-arm64-WK2-Tests/253079@main%20(339)/fast/layers/add-layer-with-nested-stacking-diff.txt