**Describe the bug**
When you set the setting `input_format_with_names_use_header` to `0`, `INSERT` does not actually insert rows.

**How to reproduce**
* Which ClickHouse server version to use: git master `a21fe0b492cbc8628126a3cd493b83e82abf9978`, checked out on 2021-03-31
* Which interface to use: the native command-line client
* Non-default settings, if any: `input_format_with_names_use_header` = `0`
* `CREATE TABLE` statements for all tables involved:
```sql
CREATE TABLE csvtest
(
    `t` String
)
ENGINE = MergeTree
ORDER BY t
```
* Sample data for all these tables
`test.csv`:
```csv
t
testdata1
testdata2
```
* Queries to run that lead to unexpected result:
```
% clickhouse-client --input_format_with_names_use_header 0 --query "INSERT INTO csvtest FORMAT CSVWithNames" < test.csv
```

**Expected behavior**
Two rows `('testdata1'), ('testdata2')` will be inserted to the table `csvtest`.

**Error message and/or stacktrace**
Nothing. It silently discards the input and inserts nothing to the table.

**Additional context**
It works as expected if you set `input_format_with_names_use_header` to `1`.

{
    while (!in.eof()
            && (*in.position() == ' '
                || *in.position() == '\t'))
        ++in.position();
}
static void skipRow(ReadBuffer & in, const FormatSettings::CSV & settings, size_t num_columns)
{
    String tmp;
    for (size_t i = 0; i < num_columns; ++i)
    {
        skipWhitespacesAndTabs(in);
        readCSVString(tmp, in, settings);
        skipWhitespacesAndTabs(in);
        skipDelimiter(in, settings.delimiter, i + 1 == num_columns);
    }
}
void CSVRowInputFormat::setupAllColumnsByTableSchema()