gfx: disable GetFallbackFont test suite on Mac

Something is wrong with the fallback font path that these tests hit,
on 10.15.1 and probably other releases.

Bug: 1022455
Change-Id: Ib82a5e27a5f0203f700363e663a08496da2df466
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1902440Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713511}

ui/gfx/font_fallback_unittest.cc

@@ -135,7 +135,13 @@ class GetFallbackFontTest
 //
 // The previous checks can be activated or deactivated through the class
 // FallbackFontTestOption (e.g. test_option_).
-TEST_P(GetFallbackFontTest, GetFallbackFont) {
+#if defined(OS_MACOSX)
+// https://crbug.com/1022455
+#define MAYBE_GetFallbackFont DISABLED_GetFallbackFont
+#else
+#define MAYBE_GetFallbackFont GetFallbackFont
+#endif
+TEST_P(GetFallbackFontTest, MAYBE_GetFallbackFont) {
   // Default system font.
   const Font base_font;