Give test files a -tests.el suffix

Rename a couple of test files that have the same name as the library
they test.  This harmonizes the naming pattern and makes it possible
to have the tests directories in the load path.

test/lisp/eshell/eshell.el → test/lisp/eshell/eshell-tests.el

-;;; tests/eshell.el --- Eshell test suite
+;;; tests/eshell-tests.el --- Eshell test suite
 
 ;; Copyright (C) 1999-2017 Free Software Foundation, Inc.
 
@@ -249,4 +249,4 @@ chars"
 
 (provide 'esh-test)
 
-;;; tests/eshell.el ends here
+;;; tests/eshell-tests.el ends here

test/lisp/net/puny.el → test/lisp/net/puny-tests.el

-;;; puny.el --- tests for net/puny.el  -*- coding: utf-8; -*-
+;;; puny-tests.el --- tests for net/puny.el  -*- coding: utf-8; -*-
 
 ;; Copyright (C) 2017 Free Software Foundation, Inc.
 
@@ -38,4 +38,4 @@
   "Test puny decoding."
   (should (string= (puny-decode-string "xn--9dbdkw") "חנוך")))
 
-;;; puny.el ends here
+;;; puny-tests.el ends here

test/lisp/progmodes/f90.el → test/lisp/progmodes/f90-tests.el

-;;; f90.el --- tests for progmodes/f90.el
+;;; f90-tests.el --- tests for progmodes/f90.el
 
 ;; Copyright (C) 2011-2017 Free Software Foundation, Inc.
 
@@ -273,4 +273,4 @@ end program prog")
     (forward-line -2)
     (should (= 2 (current-indentation))))) ; class is
 
-;;; f90.el ends here
+;;; f90-tests.el ends here

test/lisp/vc/vc-hg.el → test/lisp/vc/vc-hg-tests.el

-;;; vc-hg.el --- tests for vc/vc-hg.el
+;;; vc-hg-tests.el --- tests for vc/vc-hg.el
 
 ;; Copyright (C) 2016-2017 Free Software Foundation, Inc.
 
@@ -55,4 +55,4 @@
     (save-excursion (insert "philringnalda 218075 2014-11-28 CLOBBER:"))
     (should (floatp (vc-hg-annotate-time)))))
 
-;;; vc-hg.el ends here
+;;; vc-hg-tests.el ends here