Remove active-on-jdk-9-plus profile

The code doesn't build on earlier versions anyway

Author: oschwald

pom.xml

@@ -147,6 +147,7 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.12.1</version>
                 <configuration>
+                    <release>11</release>
                     <source>11</source>
                     <target>11</target>
                 </configuration>
@@ -187,23 +188,6 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
     <profiles>
-        <profile>
-            <id>active-on-jdk-9-plus</id>
-            <activation>
-                <jdk>[9,)</jdk>
-            </activation>
-            <build>
-                <plugins>
-                    <plugin>
-                        <artifactId>maven-compiler-plugin</artifactId>
-                        <version>3.12.1</version>
-                        <configuration>
-                            <release>11</release>
-                        </configuration>
-                    </plugin>
-                </plugins>
-            </build>
-        </profile>
         <profile>
             <id>not-windows</id>
             <!--