Fix CVE-2019-13224: don't allow different encodings for onig_new_deluxe()

[npt-1707]

Description This PR fixes a use-after-free in onig_new_deluxe() in regext.c in Oniguruma which was cloned from kkos/oniguruma@0f7f61e but did not receive the security patch. This PR applies the same patch to handle the vulnerability.

References: https://github.com/kkos/oniguruma/commit/0f7f61e https://nvd.nist.gov/vuln/detail/CVE-2019-13224

[RokeJulianLockhart]

https://github.com/kingToolbox/WindTerm/pull/2823#pullrequestreview-2788928136

@aazizmoussa, that's normal.