[OpenMP] Fix target data region codegen being omitted for device pass (#85218)

This patch enables the BodyCodeGen callback to still trigger for the
TargetData nested region during the device pass. There maybe Target code
nested within the TargetData region for which this is required.

Also add tests for the same.

GitOrigin-RevId: e9da5f0083d12a7284c780e916c17b6a2785933e
1 file changed