scripted-diff: stop using the gArgs wrappers

They were temporary additions to ease the transition.

-BEGIN VERIFY SCRIPT-
find src/ -name "*.cpp" ! -wholename "src/util.h" ! -wholename "src/util.cpp" | xargs perl -i -pe 's/(?<!\.)(ParseParameters|ReadConfigFile|IsArgSet|(Soft|Force)?(Get|Set)(|Bool|)Arg(s)?)\(/gArgs.\1(/g'
-END VERIFY SCRIPT-

src/test/net_tests.cpp

@@ -80,7 +80,7 @@ BOOST_AUTO_TEST_CASE(cnode_listen_port)
     BOOST_CHECK(port == Params().GetDefaultPort());
     // test set port
     unsigned short altPort = 12345;
-    SoftSetArg("-port", std::to_string(altPort));
+    gArgs.SoftSetArg("-port", std::to_string(altPort));
     port = GetListenPort();
     BOOST_CHECK(port == altPort);
 }