Remove dynamic translation of regression test scripts, step 2.

"git mv" all the input/*.source and output/*.source files into
the corresponding sql/ and expected/ directories.  Then remove
the pg_regress and Makefile infrastructure associated with
dynamic translation.

Discussion: https://postgr.es/m/1655733.1639871614@sss.pgh.pa.us

contrib/dblink/Makefile

@@ -13,7 +13,6 @@ PGFILEDESC = "dblink - connect to other PostgreSQL databases"
 
 REGRESS = paths dblink
 REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
-EXTRA_CLEAN = sql/paths.sql expected/paths.out
 
 ifdef USE_PGXS
 PG_CONFIG = pg_config

contrib/dblink/expected/.gitignore

@@ -1 +0,0 @@
-/paths.out

contrib/dblink/sql/.gitignore

@@ -1 +0,0 @@
-/paths.sql