`DataTypeFactory::get` locks a mutex inside shared a context, there was a case when many threads were locked inside it

https://pastila.nl/?0043b3e6/c557368f4cf0eb87a3c6f2cc162bc693

It is not clear which thread locked the mutex for a long time. However, it may be possible to lock less inside `DataTypeFactory::get`.
{
    auto lock = getLock();
    if (shared->index_mark_cache)
        throw Exception("Index mark cache has been already created.", ErrorCodes::LOGICAL_ERROR);
    shared->index_mark_cache = std::make_shared<MarkCache>(cache_size_in_bytes);
}
MarkCachePtr Context::getIndexMarkCache() const
{
    auto lock = getLock();
    return shared->index_mark_cache;
}
void Context::dropIndexMarkCache() const
{
    auto lock = getLock();
    if (shared->index_mark_cache)
        shared->index_mark_cache->reset();
}
void Context::setMMappedFileCache(size_t cache_size_in_num_entries)
{
    auto lock = getLock();
    if (shared->mmap_cache)
        throw Exception("Mapped file cache has been already created.", ErrorCodes::LOGICAL_ERROR);
    shared->mmap_cache = std::make_shared<MMappedFileCache>(cache_size_in_num_entries);
}
MMappedFileCachePtr Context::getMMappedFileCache() const