[GLIB] http/tests/performance/paint-timing/performance-paint-timing-fcp-after-visually-non-empty-for-style.html is flaky failing since added in r260851

[Lauro Moura]

http/tests/performance/paint-timing/performance-paint-timing-fcp-after-visually-non-empty-for-style.html

Results dashboard: https://results.webkit.org/?suite=layout-tests&test=http%2Ftests%2Fperformance%2Fpaint-timing%2Fperformance-paint-timing-fcp-after-visually-non-empty-for-style.html

Local results running it alone:
* GTK-xvfb: 300 runs, 11 failures.
* WPE: 300 runs, 4 failures.

On the bots, more flaky on GTK-Wayland and WPE-Release than on GTK-X11.

Diff:

--- /home/lauro/dev/WebKit/layout-test-results/http/tests/performance/paint-timing/performance-paint-timing-fcp-after-visually-non-empty-for-style-expected.txt
+++ /home/lauro/dev/WebKit/layout-test-results/http/tests/performance/paint-timing/performance-paint-timing-fcp-after-visually-non-empty-for-style-actual.txt
@@ -1,2 +1,2 @@
-PASS paintEntry.startTime >= styleEntry.startTime + styleEntry.duration is true
+FAIL paintEntry.startTime >= styleEntry.startTime + styleEntry.duration should be true. Was false.
 TEXT

[Radar WebKit Bug Importer]

<rdar://problem/75327139>

[Lauro Moura]

Both GTK/WPE started passing consistently since between (238414@main-238416@main].

Likely due to 238416@main: Fix WPT test resource-timing/cross-origin-redirects.html