tests: use 'check_PROGRAMS' instead of 'noinst_PROGRAMS'

When using 'check_PROGRAMS', autoconf/automake generates smarter
Makefiles, so that the test programs are not being compiled during
the normal 'make all', but only during 'make check'.

Change-Id: I938669a78b4afa808ca4f741aee9919944aeb7f6

tests/mgcp/Makefile.am

@@ -24,7 +24,7 @@ EXTRA_DIST = \
 	mgcp_test.ok \
 	$(NULL)
 
-noinst_PROGRAMS = \
+check_PROGRAMS = \
 	mgcp_test \
 	$(NULL)
 

tests/mgcp_client/Makefile.am

@@ -22,7 +22,7 @@ EXTRA_DIST = \
 	mgcp_client_test.err \
 	$(NULL)
 
-noinst_PROGRAMS = \
+check_PROGRAMS = \
 	mgcp_client_test \
 	$(NULL)