core: Patch to fix OverflowError when calling subsn on certain power expressions

[htrivedi04]

References to other Issues or PRs

Brief description of what is fixed or changed

This patch fixes #14704

This patch will fix the Overflow Error encountered when the value for n is too large, such that Python is not able to convert it to a float in the expression exp = _log(y,2)/n. It can be fixed simply by changing the expression to exp = int(_log(y,2))/n. Thanks @jksuom for your inputs!

For example: @DRMacIver stated in the Issue #14704 that -
from sympy.abc import a

if name == 'main':
b = a ** a
c = b ** b
c.subs({a: -144})

produces an OverflowError: int too large to convert to float. This short change fixes that

Other comments

This is my first patch for this project. Any constructive feedbacks are most appreciated! :)

[sidhantnagpal]

There is an existing PR: #14707, for the fix. You can check referencing PRs in the issue (which might attempt to fix the issue).

[Abdullahjavednesar]

The PR currently fixing the issue is active, if it fails to fix you can continue.

[kenluck2001]

Can I start my journey into sympy project with this PR?

[czgdp1807]

Closing in favour of #17636