[DWARF] Default lower bound should respect requested DWARF version.

DWARF may define a default lower-bound for arrays in languages defined
in a particular DWARF version.  But the logic to suppress an
unnecessary lower-bound attribute was looking at the hard-coded
default DWARF version, not the version that had been requested.

Also updated the list with all languages defined in DWARF v5.

Differential Revision: http://reviews.llvm.org/D30484

llvm-svn: 296652