This is required when an out argument involves an array index that is either
a global variable modified by the function or another out argument in the
same function call.
Fixes the shaders/out-parameter-indexing/vs-inout-index-inout-* tests.
v2:
- modify the ir_dereference_array nodes in place
- use ir_hierarchical_visitor
v3: use base_ir (Ian Romanick)
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>