Retiring pg_regress' --load-language option

pg_regress' --load-language option has been unused in the core code since
we introduced extensions in 9.1; all callers now use --load-extension
instead.  It's a fairly safe bet that it's never been used by any non-core
code, since it could only work for languages listed in pg_pltemplate.
The last possible reason to use it expired with commit 50fc694e4, which
removed pg_pltemplate and made parameterless CREATE LANGUAGE equivalent
to CREATE EXTENSION.  So I think we might as well kill it, as per the
attached trivial patch.  Any objections?

            regards, tom lane

diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 92bd28d..9a4e52b 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -76,7 +76,6 @@ char       *inputdir = ".";
 char       *outputdir = ".";
 char       *bindir = PGBINDIR;
 char       *launcher = NULL;
-static _stringlist *loadlanguage = NULL;
 static _stringlist *loadextension = NULL;
 static int    max_connections = 0;
 static int    max_concurrent_tests = 0;
@@ -1998,16 +1997,6 @@ create_database(const char *dbname)
                  dbname, dbname, dbname, dbname, dbname, dbname);

     /*
-     * Install any requested procedural languages.  We use CREATE OR REPLACE
-     * so that this will work whether or not the language is preinstalled.
-     */
-    for (sl = loadlanguage; sl != NULL; sl = sl->next)
-    {
-        header(_("installing %s"), sl->str);
-        psql_command(dbname, "CREATE OR REPLACE LANGUAGE \"%s\"", sl->str);
-    }
-
-    /*
      * Install any requested extensions.  We use CREATE IF NOT EXISTS so that
      * this will work whether or not the extension is preinstalled.
      */
@@ -2058,8 +2047,6 @@ help(void)
     printf(_("      --launcher=CMD            use CMD as launcher of psql\n"));
     printf(_("      --load-extension=EXT      load the named extension before running the\n"));
     printf(_("                                tests; can appear multiple times\n"));
-    printf(_("      --load-language=LANG      load the named language before running the\n"));
-    printf(_("                                tests; can appear multiple times\n"));
     printf(_("      --max-connections=N       maximum number of concurrent connections\n"));
     printf(_("                                (default is 0, meaning unlimited)\n"));
     printf(_("      --max-concurrent-tests=N  maximum number of concurrent tests in schedule\n"));
@@ -2096,7 +2083,6 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
         {"dbname", required_argument, NULL, 1},
         {"debug", no_argument, NULL, 2},
         {"inputdir", required_argument, NULL, 3},
-        {"load-language", required_argument, NULL, 4},
         {"max-connections", required_argument, NULL, 5},
         {"encoding", required_argument, NULL, 6},
         {"outputdir", required_argument, NULL, 7},
@@ -2172,9 +2158,6 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
             case 3:
                 inputdir = pg_strdup(optarg);
                 break;
-            case 4:
-                add_stringlist_item(&loadlanguage, optarg);
-                break;
             case 5:
                 max_connections = atoi(optarg);
                 break;