Remove locale tests that depend on enviroment variables.

Constructing a std::locale object from an empty string selects the language
from the current environment variables. If the environment variables name
a locale that doesn't exist, or isn't installed, then the construction of
facets using that locale may throw.

This patch removes tests that use 'std::locale l("")'.

The optimal solution would be to manually set the environment variables
in the test. Unfortunately there is no portable way to do this.

llvm-svn: 275772