This issue is a follow-up to this comment:

https://bugs.openjdk.org/browse/JDK-8290519?focusedCommentId=14512038&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14512038

It intends to fix logic in handling WiX l10n files, that appeared to be different from the expected one.

Proposed changes:

 - copy all 4 primary l10n files

 - make all 4 primary files overridable

 - pass all 4 primary l10n files to light.exe

 - resolve the duplicates between primary files and custom files

Note, one of primary l10n files will be overridden when the name of the custom user-provided l10n file is the same as the primary one. In this case default primary file is not specified to light.exe. If custom user-provided file name is different - existing handling logic is used (it is provided in addition to primary ones, its culture takes priority).