patch 8.2.3696: Vim9: error for invalid assignment when skipping

Problem:    Vim9: error for invalid assignment when skipping.
Solution:   Do not check white space when skipping. (closes #9243)

src/evalvars.c

@@ -881,7 +881,7 @@ ex_let(exarg_T *eap)
 	    else
 		++expr;
 
-	    if (vim9script && (!VIM_ISWHITE(*argend)
+	    if (vim9script && !eap->skip && (!VIM_ISWHITE(*argend)
 						   || !IS_WHITE_OR_NUL(*expr)))
 	    {
 		vim_strncpy(op, expr - len, len);

src/testdir/test_vim9_assign.vim

@@ -1854,6 +1854,12 @@ def Test_unlet()
     'var ll = [1, 2]',
     'unlet ll[0: 1]',
     ], 'E1004:', 2)
+  # command recognized as assignment when skipping, should not give an error
+  CheckScriptSuccess([
+    'vim9script',
+    'for i in []',
+    "  put =''",
+    'endfor'])
 
   CheckDefFailure([
     'var ll = [1, 2]',

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3696,
 /**/
     3695,
 /**/