chore: fix ValueRanges computation in symbolic nodes

[peri044]

Description

This PR fixes the following:

1. Sometimes there are subgraphs which receive a SymInt node (so*s1) as input ( that's the product of two other SymInt s0 and s1). However, this node (so*s1) does not have ValueRanges computed automatically but it just has the data for s0 and s1

2. It also adds support for operator.mul. This operator gets added in the added test_linear test case where it computes product of first two dimensions (which are SymInt nodes). Since SymInt nodes are handled as shape tensors in TensorRT, our existing converter for mul operators can be used for this operator.

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]

Context: pytorch/pytorch#128640

[gs-olive]

Overall looks good - added two clarifying comments

[gs-olive]

Looks good to me, pending CI