Remove coverage test cases

Coverage test cases are only for white-box test during development
of some RAS features in the kernel. By now it is totally obsolete.
Mask these test cases to avoid confusing users.

It will be removed from the test suite after some time, if no one
has complainant.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
diff --git a/README b/README
index 524716b..e27ab23 100644
--- a/README
+++ b/README
@@ -84,7 +84,8 @@
 For futher information about MCE test suite, please refer to documents
 in doc sub-directory.
 
-doc/howto.txt:		a more detailed HOWTO document
+doc/howto.txt:		a more detailed HOWTO document. This doc is a little
+			bit out of date.
 
 doc/stress-howto.txt:	Detailed HOWTO document for MCE stress test suite
 
diff --git a/groups/coverage b/groups/coverage
index ef51a95..b0376a0 100644
--- a/groups/coverage
+++ b/groups/coverage
@@ -1,5 +1,5 @@
 #Coverage test is out-of-date, it is not guaranteed
 #working well with newer kernel
 
-SIMPLE cases/coverage/soft-inj/run_simple.sh off
+#SIMPLE cases/coverage/soft-inj/run_simple.sh off
 #KDUMP cases/coverage/soft-inj/run_kdump.sh off