Don't run rustdoc test in normal test cycle

Author: marijnh

mk/tests.mk

@@ -139,7 +139,7 @@ check-stage$(1)-T-$(2)-H-$(3): tidy				\
 	check-stage$(1)-T-$(2)-H-$(3)-cfail			\
 	check-stage$(1)-T-$(2)-H-$(3)-bench			\
 	check-stage$(1)-T-$(2)-H-$(3)-pretty                    \
-        check-stage$(1)-T-$(2)-H-$(3)-rustdoc                   \
+#        check-stage$(1)-T-$(2)-H-$(3)-rustdoc                   \
         check-stage$(1)-T-$(2)-H-$(3)-doc-tutorial
 
 check-stage$(1)-T-$(2)-H-$(3)-core:				\