isStandalone property: remove dependency on pretty-print

Summary

Change the behavior of the isStandalone property so that it takes effect regardless of the settings of the pretty-print property.

Problem

The new implementation specific property isStandalone added through JDK-8249867 required the property format-pretty-print to be true. However, there are cases where applications want the serializer to produce an output with a newline after the header but without setting the pretty-print property.

Solution

Remove the dependency on the pretty-print property.

Specification

JDK16u and Oracle JDK11u

The javadoc will be exactly the same as described in the JDK17 CSR (https://bugs.openjdk.java.net/browse/JDK-8261210). In the implementation note of the module summary (java.xml/module-info.java), specifically in table Features and Properties, remove when the property format-pretty-print is set to true from the property description.

A link is provided below for convenience:

http://cr.openjdk.java.net/~joehw/jdk17/8261209/spec_01/java.xml/module-summary.html

Oracle JDK8u and Oracle JDK7u

The release note subtask (https://bugs.openjdk.java.net/browse/JDK-8259502) is clarified with above content.