Gensrc step CompileProperties generates unstable CompilerProperties output

The classes CompilerProperties and it's nested subclasses is created by the CompileProperties tool. However, it intermittently fails the reproducibility test; that is, different source code is generated on subsequent runs.

The COMPARE_BUILD output is typically like this:
jib > Zip/tar.gz files...
jib > Differing files in ./lib/src.zip
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties.java
jib > sec-bin.zip...
jib > sec-windows-bin.zip...
jib > jgss-windows-x64-bin.zip...
jib > Jar files...
jib > Differing files in ./lib/modules
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties$Errors.class
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties$Fragments.class
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties$Notes.class
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties$Warnings.class
jib > /jdk.compiler/com/sun/tools/javac/resources/CompilerProperties.class

As usually with unstable build output, this happens much more frequently on Windows.