N1QL: test_array_index_regexp_covering fails,query with regular expression times out on centos and windows,panic seen in query.log

Side affect of MB-23372

Test which fails:

./testrunner -i /tmp/n1ql_set4.ini get-cbcollect-info=True -t tuqquery.tuq_2i_index.QueriesIndexTests.test_array_index_regexp_covering,index_type=GSI,array_indexing=True

Test runs on a 4 node cluster.

What the test does?
1. create an index:
self.query = " CREATE INDEX %s ON %s( DISTINCT ARRAY REGEXP_LIKE(v.os,%s) FOR v IN VMs END,VMs ) USING %s" % (idx, bucket.name,"'ub%'", self.index_type)

2. select * from system:indexes to verify the index got created.

3. Issue an explain query to check the plan:
self.query = "EXPLAIN select VMs from %s WHERE ANY v IN VMs SATISFIES REGEXP_LIKE(v.os,%s) = 1 END " % (bucket.name,"'ub%'") + "limit 10"

Error reported by test:

[2017-03-31 12:52:03,020] - [rest_client:788] ERROR - socket error while connecting to http://172.23.106.234:8093/query?scan_consistency=REQUEST_PLUS&statement=EXPLAIN+select+VMs+from+default++WHERE+ANY+v+IN+VMs+SATISFIES+REGEXP_LIKE%28v.os%2C%27ub%25%27%29+%3D+1+END++limit+10 error timed out 

Same issue is seen on windows also.
Attaching logs.