[IR] Implement methods to check dynamism on Shape

[justinchuby]

Define is_static() and is_dynamic() on Shape. Users can check if the shape is static/dynamic, or if a specific axis is static/dynamic.

Fixes #1950

[codecov]

Codecov Report

Attention: Patch coverage is 97.91667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.97%. Comparing base (e6e3d52) to head (4d76da3).
Report is 2 commits behind head on main.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
onnxscript/ir/_core.py	93.75%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1952      +/-   ##
==========================================
+ Coverage   74.89%   74.97%   +0.08%     
==========================================
  Files         262      262              
  Lines       28467    28558      +91     
  Branches     3284     3289       +5     
==========================================
+ Hits        21320    21411      +91     
- Misses       6138     6139       +1     
+ Partials     1009     1008       -1     

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[titaiwangms]

Do you think a method return whether the Shape is static or not would be another useful method? (When users do not want to go through all dims one by one.)

[justinchuby]

Do you think a method return whether the Shape is static or not would be another useful method? (When users do not want to go through all dims one by one.)

Sure! Basically we can make shape.is_static() return this info

[justinchuby]

Do you think a method return whether the Shape is static or not would be another useful method? (When users do not want to go through all dims one by one.)

Sure! Basically we can make shape.is_static() return this info

Done