REGRESSION: (r243224 - r243230) Layout Test printing/width-overflow.html and inspector/css/shadow-scoped-style.html are failing

[Truitt Savell]

The following layout tests ar failing on Mac

printing/width-overflow.html 
inspector/css/shadow-scoped-style.html

Probable cause:

These two tests began failing at the same time. I was able to reproduce the failures on a release build of 243230. there is a gap in builds between that and 243224 which doesn't have a failure. I can't reproduce the failures in debug. 

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=printing%2Fwidth-overflow.html

Diff:
--- /Volumes/Data/slave/mojave-release-tests-wk1/build/layout-test-results/inspector/css/shadow-scoped-style-expected.txt
+++ /Volumes/Data/slave/mojave-release-tests-wk1/build/layout-test-results/inspector/css/shadow-scoped-style-actual.txt
@@ -21,6 +21,8 @@
 }
 address, article, aside, div, footer, header, hgroup, layer, main, nav, section {
 }
+html {
+}
 
 -- Running test case: CSS.ShadowScopedStyle.ElementInShadowTree
 PASS: Node should not have shadow roots.

Diff:
https://build.webkit.org/results/Apple%20Mojave%20Release%20WK1%20(Tests)/r243246%20(3825)/printing/width-overflow-diff.txt

[Radar WebKit Bug Importer]

<rdar://problem/49158428>

[Alexey Proskuryakov]

These were both fixed with a rebaseline by xenon in r243257: "Unreviewed test gardening after r243229."