Do not build tests if not requested to.

--- a/GNUmakefile.am	2010-12-21 17:23:58.000000000 +0100
+++ b/GNUmakefile.am	2010-12-21 17:24:28.000000000 +0100
@@ -46,7 +46,8 @@
 
 # Libraries and support components
 bin_PROGRAMS :=
+check_PROGRAMS :=
 noinst_PROGRAMS :=
 noinst_HEADERS :=
 noinst_LTLIBRARIES :=
 lib_LIBRARIES :=
@@ -541,7 +541,7 @@
 include WebKit/gtk/po/GNUmakefile.am
 
 # Build unit tests
-noinst_PROGRAMS += $(TEST_PROGS)
+check_PROGRAMS += $(TEST_PROGS)
 
 webkit_tests_cflags = \
 	-fno-strict-aliasing \