Enable mus_browser_tests on trybot

testing/buildbot/filters/mus.browser_tests.filter

Index: testing/buildbot/filters/mus.browser_tests.filter
diff --git a/testing/buildbot/filters/mus.browser_tests.filter b/testing/buildbot/filters/mus.browser_tests.filter
index 548a1e445a9ac39c89634b32616803e6ad4b7bd8..6e8aee8acc17530e42e25063b00fae347538f3ee 100644
--- a/testing/buildbot/filters/mus.browser_tests.filter
+++ b/testing/buildbot/filters/mus.browser_tests.filter
@@ -64,9 +64,6 @@ DeviceStatusCollectorTest.TestVolumeInfo
 DeviceStatusCollectorTest.Times
 DeviceStatusCollectorTest.VersionInfo
 DownloadInterruptReasonEnumsSynced.DownloadInterruptReasonEnumsSynced
-ExtensionDetermineDownloadFilenameInternal.ExtensionDetermineDownloadFilenameInternal
-FolderShortcuts/FileManagerBrowserTest.Test/0
-FolderShortcuts/FileManagerBrowserTest.Test/1
 FormAutocompleteTest.AjaxSucceeded_FilledFormIsInvisible
 FormAutocompleteTest.AjaxSucceeded_FilledFormStillVisible
 FormAutocompleteTest.AjaxSucceeded_FormlessElements
@@ -98,16 +95,6 @@ FormClassifierTest.SomeFormWithoutPasswordFields
 FormClassifierTest.kChangeFormWithTreePasswordFieldsHTML
 InstantProcessNavigationTest.ForkForNavigationsFromInstantProcess
 InstantProcessNavigationTest.ForkForNavigationsToSearchURLs
-MultiProfileFileManagerBrowserTest.BasicDownloads
-MultiProfileFileManagerBrowserTest.BasicDrive
-OpenAudioFiles/FileManagerBrowserTest.Test/1
-OpenAudioFiles/FileManagerBrowserTest.Test/2
-OpenAudioFiles/FileManagerBrowserTest.Test/3
-OpenAudioFiles/FileManagerBrowserTest.Test/4
-OpenAudioFiles/FileManagerBrowserTest.Test/5
-OpenAudioFiles/FileManagerBrowserTest.Test/6
-OpenAudioFiles/FileManagerBrowserTest.Test/7
-OpenAudioFiles/FileManagerBrowserTest.Test/8
 PageClickTrackerTest.PageClickTrackerClickDisabledInputDoesNotResetClickCounter
 PageClickTrackerTest.PageClickTrackerDisabledInputClickedNoEvent
 PageClickTrackerTest.PageClickTrackerInputClicked