patch 9.1.0703: crash with 2byte encoding and glob2regpat()

Problem:  possible crash with 2-byte encoding and glob2regpat()
          (after v9.1.0700, v9.1.0702)
Solution: include both bytes for a multi-byte character for an
          escaped character

closes: #15590

Signed-off-by: Christian Brabandt <cb@256bit.org>

Author: chrisbra

src/fileio.c

@@ -5714,6 +5714,8 @@ file_pat_to_reg_pat(
 				)
 			    *allow_dirs = TRUE;
 			reg_pat[i++] = '\\';
+			if (enc_dbcs != 0 && (*mb_ptr2len)(p) > 1)
+			    reg_pat[i++] = *p++;
 			reg_pat[i++] = *p;
 		    }
 		break;

src/testdir/test_crash.vim

@@ -222,11 +222,11 @@ func Test_crash1_3()
   call term_sendkeys(buf, args)
   call TermWait(buf, 150)
 
-  " let file = 'crash/heap_overflow_glob2regpat'
-  " let cmn_args = "%s -u NONE -i NONE -n -X -m -n -e -s -S %s -c ':qa!'"
-  " let args = printf(cmn_args, vim, file)
-  " call term_sendkeys(buf, args)
-  " call TermWait(buf, 50)
+  let file = 'crash/heap_overflow_glob2regpat'
+  let cmn_args = "%s -u NONE -i NONE -n -X -m -n -e -s -S %s -c ':qa!'"
+  let args = printf(cmn_args, vim, file)
+  call term_sendkeys(buf, args)
+  call TermWait(buf, 50)
 
   let file = 'crash/nullptr_regexp_nfa'
   let cmn_args = "%s -u NONE -i NONE -n -X -m -n -e -s -S %s -c ':qa!'"

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    703,
 /**/
     702,
 /**/