Fix hex literal parsing (#29935)
Summary:
Stacked PRs
* #29940 - [jit] Fix parsing of big float literals
* **#29935 - [jit] Fix hex literal parsing**
* #29931 - [jit] Throw a better error for int too big for int64_t
Previously these were all parsed as `0`
](https://our.intern.facebook.com/intern/diff/19124944/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29935
Pulled By: driazati
Differential Revision: D19124944
fbshipit-source-id: 1ee0c1dee589933363a5efba069a2cfaf94373c5
