patch 8.2.1709: Vim9: memory leak when using multiple closures

Problem:    Vim9: memory leak when using multiple closures.
Solution:   Free the partial.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1709,
 /**/
     1708,
 /**/

src/vim9execute.c

@@ -1830,6 +1830,7 @@ call_def_function(
 			    // TODO: use a garray_T on ectx.
 			    SOURCING_LNUM = iptr->isn_lnum;
 			    emsg("Multiple closures not supported yet");
+			    vim_free(pt);
 			    goto failed;
 			}
 			tv->v_type = VAR_PARTIAL;