### Description

Evals that introduce aliased can be simplified by extracting them into a project (and thus signaling there's no underlying processing).

The following eval:
`eval x = a + 1, y = x, z = y + 1, y = z, w = y + 1`
can be converted into:
`eval x = a + 1, z = a + 1 + 1, w = a + 1 + 1 | project x, z, z as y, w`

This helps fuse the project with other projections/aggs downstream.
x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestUtils.java
import org.elasticsearch.xpack.esql.action.EsqlQueryResponse;
import org.elasticsearch.xpack.ql.util.StringUtils;
import org.elasticsearch.xpack.versionfield.Version;
import org.supercsv.io.CsvListReader;
import org.supercsv.prefs.CsvPreference;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.math.BigDecimal;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.function.Function;
import static org.elasticsearch.common.Strings.delimitedListToStringArray;
import static org.elasticsearch.common.logging.LoggerMessageFormat.format;
import static org.elasticsearch.xpack.ql.SpecReader.shouldSkipLine;
import static org.elasticsearch.xpack.ql.type.DataTypeConverter.safeToUnsignedLong;
import static org.elasticsearch.xpack.ql.util.DateUtils.UTC_DATE_TIME_FORMATTER;
import static org.elasticsearch.xpack.ql.util.NumericUtils.asLongUnsigned;
public final class CsvTestUtils {
    private static final int MAX_WIDTH = 20;
    private static final CsvPreference CSV_SPEC_PREFERENCES = new CsvPreference.Builder('"', '|', "\r\n").build();
    private static final String NULL_VALUE = "null";
    private CsvTestUtils() {}