Build Catalan-Valencian as ca-valencia instead of ca-XV private-use.

Introduced LANGUAGE_CATALAN_VALENCIAN 0x0803 mapping to ca-ES-valencia,
preserving old ca-XV and qcv-ES mappings to now
LANGUAGE_CATALAN_VALENCIAN and LANGUAGE_OBSOLETE_USER_CATALAN_VALENCIAN
0x8003 to ca-ES-valencia.

Removed special !bUserInterfaceSelection treatment from
MsLangId::getReplacementForObsoleteLanguage() and added the usual
obsolete replacement instead.

Change-Id: I2fdd8b0bac55d4b4ae2cbf3c3645f09fefec9b6e