compilers: Don't use CompilerArgs() for sanity checks

It's only useful to use those when you have to override include dirs
or library paths by appending them from various sources according to
the priority order, or if the compiler args need to be converted from
Unix/GCC-style to native (MSVC, for instance) style.

Sanity checks match neither of these.

Closes https://github.com/mesonbuild/meson/issues/1351

mesonbuild/compilers.py

@@ -601,7 +601,7 @@ class Compiler:
                 self.language))
 
     def get_cross_extra_flags(self, environment, *, compile, link):
-        extra_flags = CompilerArgs(self)
+        extra_flags = []
         if self.is_cross and environment:
             if 'properties' in environment.cross_info.config:
                 lang_args_key = self.language + '_args'
@@ -831,7 +831,7 @@ class CCompiler(Compiler):
         mlog.debug('Sanity testing ' + self.language + ' compiler:', ' '.join(self.exelist))
         mlog.debug('Is cross compiler: %s.' % str(self.is_cross))
 
-        extra_flags = CompilerArgs(self)
+        extra_flags = []
         source_name = os.path.join(work_dir, sname)
         binname = sname.rsplit('.', 1)[0]
         if self.is_cross: