Remove vector sections (shared) utility

[MichaelSt98]

section_mapper = {s: s.body for s in FindNodes(ir.Section).visit(routine.body) if s.label == 'vector_section'}
if section_mapper:
    routine.body = Transformer(section_mapper).visit(routine.body)

However, quoting @reuterbal

a custom in-place transformer be more efficient here, that hooks into visit_tuple to inline Section bodies? That would save the
double traversal+rebuild.