Two fixes involving minimal builds (#17000)
### Description
<!-- Describe your changes. -->
- allocation planner was breaking if graph had no nodes
- in this particular model a branch of an If node returned an outer
scope value directly.
- if model used non-tensor types and sparse tensors are disabled the
call to IsSpareTensor causes an exception when prematurely terminates
the code.
- it's perfectly fine to check if a value is a sparse tensor when
support for them is disabled. we just can't do anything with that
OrtValue which is what the current ifdef's after the call to
IsSparseTensor handle.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
Fix model execution failure for partner with model that uses sequences
in a minimal build with sparse tensors disabled.
