Fix more unstable tests

Similar to what was done in 457cdce61d, and for the same reason.

However, instead of waiting and fixing them one by one as we see them fail, I
decided to go about it more systematically. To do that, I added calls to
`time.Sleep(1 * time.Second)` in all the Shell.Commit* helper functions; this
ensures that all the commits we make get different committer time stamps, making
all these tests fail. With this I'm pretty confident that we're good now.

pkg/integration/tests/custom_commands/suggestions_command.go

@@ -37,6 +37,8 @@ var SuggestionsCommand = NewIntegrationTest(NewIntegrationTestArgs{
 				},
 			},
 		}
+
+		cfg.GetUserConfig().Git.LocalBranchSortOrder = "alphabetical"
 	},
 	Run: func(t *TestDriver, keys config.KeybindingConfig) {
 		t.Views().Branches().