Backport of pcre2-10.48-Check-JIT-mode-before-validation.patch

Backport of pcre2-10.48-Check-JIT-mode-before-validation.patch

Cherry-pick of f67db227af31bba7cdf2a7a00b97af91b588c2f5 and e2f100156b94cf85dce9046b47a3274590487de4

Fix pcre2_match to check for JIT support before JIT validation & execution (#926)

This fixes the issue that the JIT branch's UTF validation is not pinned to be identical to the interpreter's validation.

This was not robust, and lead to a bug, in the case where the JIT UTF validation is done, but because the relevant JIT mode was not compiled, it falls through to the interpreter and skips the interpreter's own UTF validation and setup.

Add a testcase for #926 (#940)

(cherry picked from commit ab7097fbde778e0e4d17752ba2a14a7430d35385)