fix: remove racy syncTimeCh length assertions in big segment sync tests (#624)

The `len(storeMock.syncTimeCh) == 0` checks race with the sync
goroutine which, after writing to patchCh, can complete remaining
polls, connect the stream, and call setSynced() before the test
checks the channel length. The meaningful behaviors are already
covered by patch, poll request, and sync time assertions.

Author: keelerm84

internal/bigsegments/sync_test.go

@@ -226,7 +226,6 @@ func TestSyncSendsUpdates(t *testing.T) {
 			pollReq1 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq1, "")
 			requirePatch(t, storeMock, poll1Patch1)
-			require.Equal(t, 0, len(storeMock.syncTimeCh))
 
 			pollReq2 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq2, poll1Patch1.Version)
@@ -305,7 +304,6 @@ func TestSyncSkipsOutOfOrderUpdateFromPoll(t *testing.T) {
 			pollReq1 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq1, "")
 			requirePatch(t, storeMock, patch1)
-			require.Equal(t, 0, len(storeMock.syncTimeCh))
 
 			pollReq2 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq2, patch1.Version)
@@ -382,7 +380,6 @@ func TestSyncSkipsOutOfOrderUpdateFromStreamAndRestartsStream(t *testing.T) {
 			pollReq1 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq1, "")
 			requirePatch(t, storeMock, patch1)
-			require.Equal(t, 0, len(storeMock.syncTimeCh))
 
 			pollReq2 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq2, patch1.Version)
@@ -471,7 +468,6 @@ func TestSyncRetryIfStreamFails(t *testing.T) {
 			pollReq1 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq1, "")
 			requirePatch(t, storeMock, patch1)
-			require.Equal(t, 0, len(storeMock.syncTimeCh))
 
 			pollReq2 := helpers.RequireValue(t, requestsCh, time.Second)
 			assertPollRequest(t, pollReq2, patch1.Version)