do not free() stack allocated buffer

src/os/win32/ngx_files.c

diff --git a/src/os/win32/ngx_files.c b/src/os/win32/ngx_files.c
index a6350ce..415458b 100644
--- a/src/os/win32/ngx_files.c
+++ b/src/os/win32/ngx_files.c
@@ -575,7 +575,6 @@
         n = ngx_utf8_decode(&p, 4);
 
         if (n > 0xffff) {
-            free(utf16);
             ngx_set_errno(NGX_EILSEQ);
             return NULL;
         }