perf: Disable multitab:misc:typical24 on win7 & mac

The test has been timing out on mac and win-7. So disable.

NOTRY=true
TBR=perezju@chromium.org
BUG=944978, 946495

Change-Id: I6d1c757c603cd4998e7ea47c534a0e643a589949
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1541470Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644877}

tools/perf/expectations.config

@@ -267,8 +267,8 @@ crbug.com/676336 [ Mac ] system_health.memory_desktop/browse:news:hackernews [ S
 crbug.com/649392 [ Win ] system_health.memory_desktop/play:media:soundcloud [ Skip ]
 crbug.com/649392 [ All ] system_health.memory_desktop/play:media:google_play_music [ Skip ]
 crbug.com/742475 [ Mac ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
+crbug.com/946495 [ Mac ] system_health.memory_desktop/multitab:misc:typical24:2018 [ Skip ]
 crbug.com/838504 [ Linux ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
-crbug.com/874803 [ Win_10 ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
 crbug.com/773084 [ Mac ] system_health.memory_desktop/browse:tools:maps [ Skip ]
 crbug.com/664661 [ Mac ] system_health.memory_desktop/load:games:miniclip [ Skip ]
 crbug.com/728464 [ All ] system_health.memory_desktop/browse:social:twitter_infinite_scroll [ Skip ]
@@ -284,6 +284,8 @@ crbug.com/799734 [ Win ] system_health.memory_desktop/browse:media:tumblr [ Skip
 crbug.com/899887 [ Linux ] system_health.memory_desktop/browse:social:facebook_infinite_scroll:2018 [ Skip ]
 crbug.com/924330 [ Linux ] system_health.memory_desktop/browse:media:pinterest:2018 [ Skip ]
 crbug.com/927758 [ Desktop ] system_health.memory_desktop/load:games:alphabetty [ Skip ]
+crbug.com/874803 [ Win_10 ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
+crbug.com/944978 [ Win_7 ] system_health.memory_desktop/multitab:misc:typical24 [ Skip ]
 crbug.com/934270 [ Win ] system_health.memory_desktop/multitab:misc:typical24:2018 [ Skip ]
 crbug.com/942952 [ ChromeOS ] system_health.memory_desktop/browse:news:hackernews:2018 [ Skip ]