UnitTests: Fix names and disable slow tests by default

Slow and very slow tests have now their own test category. We add SlowTest
for tests which are slower than ~5ms and VerySlowTest if they are slower
than ~100ms. They are disabled them by "-*SlowTest.*". If you have a faster
machine than most developers simply try lower values. The aim is that most
developers can execute the tests in under ~2s.

In the long run we should use dependency breaking and data sharing to
reduce the count of the slow tests.

Change-Id: I8578071258d7f89b2052709f3dd526ced811483f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

tests/unit/unittest/sqlitedatabasebackend-test.cpp

@@ -43,6 +43,8 @@ protected:
     ::SqliteDatabaseBackend databaseBackend;
 };
 
+using SqliteDatabaseBackendSlowTest = SqliteDatabaseBackend;
+
 TEST_F(SqliteDatabaseBackend, OpenAlreadyOpenDatabase)
 {
     ASSERT_THROW(databaseBackend.open(databaseFilePath), SqliteException);
@@ -64,7 +66,7 @@ TEST_F(SqliteDatabaseBackend, DefaultJournalMode)
     ASSERT_THAT(databaseBackend.journalMode(), JournalMode::Delete);
 }
 
-TEST_F(SqliteDatabaseBackend, WalJournalMode)
+TEST_F(SqliteDatabaseBackendSlowTest, WalJournalMode)
 {
     databaseBackend.setJournalMode(JournalMode::Wal);