Continuation of:
D69116
Contributes to a fix for PR43559:
https://bugs.llvm.org/show_bug.cgi?id=43559
See also D69099 and D69116
Use the TLI hook in DAGCombine.cpp to guard against creating
shift nodes that are not optimal for a target.
Patch by: @joanlluch (Joan LLuch)
Differential Revision: https://reviews.llvm.org/D69120