Revert "Feat: Record serialization/deserialization (#1706)" (#1833)

This reverts commit f5613b4.

google-cloud-firestore/pom.xml

@@ -321,61 +321,5 @@
         </dependency>
       </dependencies>
     </profile>
-    <profile>
-      <!-- JDK17 set up for tests in src/test-jdk17 -->
-      <id>java17-test</id>
-      <activation>
-        <jdk>17</jdk>
-      </activation>
-      <build>
-        <plugins>
-          <plugin>
-            <groupId>org.codehaus.mojo</groupId>
-            <artifactId>build-helper-maven-plugin</artifactId>
-            <executions>
-              <execution>
-                <id>add-test-source</id>
-                <phase>generate-test-sources</phase>
-                <goals>
-                  <goal>add-test-source</goal>
-                </goals>
-                <configuration>
-                  <sources>
-                    <source>src/test-jdk17/java</source>
-                  </sources>
-                </configuration>
-              </execution>
-            </executions>
-          </plugin>
-          <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
-            <artifactId>maven-compiler-plugin</artifactId>
-            <inherited>true</inherited>
-            <configuration>
-              <!-- Enable Java 17 for all sources so that Intellij picks the right language level -->
-              <source>17</source>
-              <release>17</release>
-              <compilerArgs>
-                <arg>-parameters</arg>
-                <arg>--add-opens=java.base/java.lang=ALL-UNNAMED</arg>
-                <arg>--add-opens=java.base/java.util=ALL-UNNAMED</arg>
-              </compilerArgs>
-            </configuration>
-          </plugin>
-          <plugin>
-            <!-- On CI, javadoc runs on java 17, but it sources java8 to compile and raises version conflict -->
-            <groupId>org.apache.maven.plugins</groupId>
-            <artifactId>maven-javadoc-plugin</artifactId>
-            <configuration>
-              <sourceFileIncludes> 
-                <include>src/test-jdk17/**/*.java</include> 
-              </sourceFileIncludes>
-              <source>17</source>
-              <release>17</release> 
-            </configuration>
-          </plugin>
-        </plugins>
-      </build>
-    </profile>
   </profiles>
 </project>

google-cloud-firestore/src/main/java/com/google/cloud/firestore/CollectionReference.java

@@ -22,7 +22,6 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.api.gax.rpc.ApiExceptions;
 import com.google.api.gax.rpc.UnaryCallable;
-import com.google.cloud.firestore.encoding.CustomClassMapper;
 import com.google.cloud.firestore.spi.v1.FirestoreRpc;
 import com.google.cloud.firestore.telemetry.TraceUtil;
 import com.google.cloud.firestore.telemetry.TraceUtil.Scope;