Revert "Remove references to legacy Java 9 classes"

[pshipton]

Reverts #4352

Apparently the travis build wasn't sufficient, as #4352 seems to be causing build failures.
i.e. https://ci.eclipse.org/openj9/job/Build-JDK8-aix_ppc-64_cmprssptrs/1017

12:47:35 /home/u0020236/workspace/Build-JDK8-aix_ppc-64_cmprssptrs/build/aix-ppc64-normal-server-release/jdk/j9jcl_sources/jdk/src/share/classes/java/lang/System.java:152: error: package com.ibm.jvm.io does not exist
12:47:35 		setErr(com.ibm.jvm.io.ConsolePrintStream.localize(new BufferedOutputStream(new FileOutputStream(FileDescriptor.err)), true));
12:47:35 		                     ^
12:47:35 /home/u0020236/workspace/Build-JDK8-aix_ppc-64_cmprssptrs/build/aix-ppc64-normal-server-release/jdk/j9jcl_sources/jdk/src/share/classes/java/lang/System.java:153: error: package com.ibm.jvm.io does not exist
12:47:35 		setOut(com.ibm.jvm.io.ConsolePrintStream.localize(new BufferedOutputStream(new FileOutputStream(FileDescriptor.out)), true));
12:47:35 		                     ^