Do not link tests against both libor.a and libor-testing.a

Also, put libor-testing.a at a better position in the list of
libraries, to avoid linker errors.

This is a fix, or part of a fix, for 18490.

changes/build18490

@@ -0,0 +1,4 @@
+  o Minor bugfixes (build):
+    - Do not link the unit tests against both the testing and non-testing
+      versions of the static libraries. Fixes bug 18490; bugfix on
+      0.2.7.1-alpha.

src/test/include.am

@@ -151,9 +151,12 @@ src_test_test_switch_id_LDADD = \
 
 src_test_test_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
         @TOR_LDFLAGS_libevent@
-src_test_test_LDADD = src/or/libtor-testing.a src/common/libor-testing.a \
-	src/common/libor-crypto-testing.a $(LIBKECCAK_TINY) $(LIBDONNA) \
-	src/common/libor.a src/common/libor-event-testing.a \
+src_test_test_LDADD = src/or/libtor-testing.a \
+	src/common/libor-crypto-testing.a \
+	$(LIBKECCAK_TINY) \
+	$(LIBDONNA) \
+	src/common/libor-testing.a \
+	src/common/libor-event-testing.a \
 	src/trunnel/libor-trunnel-testing.a \
 	@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ \
 	@TOR_OPENSSL_LIBS@ @TOR_LIB_WS32@ @TOR_LIB_GDI@ @CURVE25519_LIBS@ \