Remove uninitialized const global g_GbFontNameMap.

C++11 makes uninitialized const PODs an error, because they contain
uninitialized memory (they're uninitialized that can never be initialized
(because they're const).

In this case, the memory was only used by _GetSubFontName() if the lang
parameter was 1, but _GetSubFontName() is only called from one place, with
a lang parameter of 0. So remove _GetSubFontName()'s lang parameter too.

(Using bsearch for searching an array that always has exactly 2 entries is
overkill too, but I'm trying to keep the diff small.)

No intended behavior change. Fixes this error on the clang/win bot:
..\..\third_party\pdfium\core\src\fxge\win32\fx_win32_device.cpp(207,20) :  error(clang): default initialization of an object of const type 'const _FontNameMap [1]'
const _FontNameMap g_GbFontNameMap[1];
                   ^

BUG=chromium:82385
R=bo_xu@foxitsoftware.com

Review URL: https://codereview.chromium.org/369343003
1 file changed