Allow all single-element tensors as value for ConstantOfShape

[justinchuby]

Updated enforcement conditions to allow any dimensional tensor with a single element according to the ONNX spec.

Fix #26218 Fix #26265

[Copilot]

Pull Request Overview

This PR relaxes the previous restriction that the ConstantOfShape "value" attribute must be a 1-D tensor of size 1, aligning behavior with the ONNX spec allowing any shape as long as it contains exactly one element.

• Removed hard enforcement of dims_size()==1 and dims()[0]==1
• Added a comment indicating intent to allow any dimensional single-element tensor

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[snnn]

LGTM!

[snnn]

I agree with the suggestion to use a range-based for loop. Since we are using C++17, a range-based for loop would be more modern and readable than std::accumulate for calculating the product of dimensions.

For example:

int64_t size = 1;
for (auto dim : t_proto_p->dims()) {
    size *= dim;
}

This is also in line with suggestions from other reviewers.

[yuslepukhin]

[yuslepukhin]