Merge branches 'consolidate.2019.04.09a', 'doc.2019.03.26b', 'fixes.2019.03.26b'...

consolidate.2019.04.09a: Lingering RCU flavor consolidation cleanups.
doc.2019.03.26b: Documentation updates.
fixes.2019.03.26b: Miscellaneous fixes.
srcu.2019.03.26b: SRCU updates.
stall.2019.03.26b: RCU CPU stall warning updates.
torture.2019.03.26b: Torture-test updates.

diff --cc kernel/rcu/rcutorture.c
Simple merge

diff --cc kernel/rcu/tree.c
Simple merge

diff --cc kernel/rcu/tree_exp.h
Simple merge

diff --cc kernel/rcu/tree_plugin.h
Simple merge