Port 1 z/OS file from Java 11 z/OS

1 file was manually ported from Java 11 z/OS:
src/jdk.compiler/share/classes/com/sun/tools/javac/file/BaseFileManager.java

The compilation was successful using the following command:
/root/jdk-17.0.3+7/bin/javac -g -source 17 -target 17 --patch-module jdk.compiler=/root/o9-17/openj9-openjdk-jdk17-zos/src/
jdk.compiler/share/classes -d .modules/jdk.compiler src/jdk.compiler/share/classes/com/sun/tools/javac/file/BaseFileManager.java

Signed-off-by: Danja Papajani <danja.papajani@ibm.com>

src/jdk.compiler/share/classes/com/sun/tools/javac/file/BaseFileManager.java

@@ -22,6 +22,11 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2019, 2019 All Rights Reserved
+ * ===========================================================================
+ */
 
 package com.sun.tools.javac.file;
 
@@ -309,6 +314,10 @@ private String getDefaultEncodingName() {
         return defaultEncodingName;
     }
 
+    public String getRawEncodingName() {
+	return encodingName;
+    }
+
     public String getEncodingName() {
         return (encodingName != null) ? encodingName : getDefaultEncodingName();
     }