scalar_to_tensor avoid scalar.to<float>()

[Njuapp]

Description

Use scalar_to_tensor as much as possible in element_wise.cpp to avoid scalar.to<float>() which aggressively casts scalar to float. All tests passed.

Fixes #1447

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[peri044]

LGTM