mdbx: fix SIGSEGV/invalid-deref/invalid-free inside env_close() when mdbx_env_open() failed in re-open case (backport).

Thanks to [@leisim](https://t.me/leisim) for [reporting](https://t.me/libmdbx/3946) this issue.

ChangeLog.md

@@ -7,6 +7,10 @@ Fixes:
 
  - Fixed insignificant typo of `||` inside `#if` byte-order condition (backport).
 
+ - Fixed`SIGSEGV` or an erroneous call to `free()` in situations where
+   errors occur when reopening by `mdbx_env_open()` of a previously used
+   environment (backport).
+
 
 ## v0.11.13 (Swashplate) at 2022-11-10
 

src/core.c

@@ -13447,9 +13447,10 @@ __cold static int mdbx_env_close0(MDBX_env *env) {
   }
 
   if (env->me_dbxs) {
-    for (unsigned i = env->me_numdbs; --i >= CORE_DBS;)
+    for (unsigned i = CORE_DBS; i < env->me_numdbs; ++i)
       mdbx_free(env->me_dbxs[i].md_name.iov_base);
     mdbx_free(env->me_dbxs);
+    env->me_numdbs = CORE_DBS;
     env->me_dbxs = nullptr;
   }
   if (env->me_pbuf) {