patch 9.0.1876: Vim9: parsing commands with newlines wrong

Problem:  Vim9: parsing commands with newlines wrong
Solution: Accept a '\n' for parsing lists and command arguments

closes: #13015
closes: #13020

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

src/testdir/test_crash.vim

@@ -62,7 +62,6 @@ func Test_crash1()
 
   let file = 'crash/vim_regsub_both_poc'
   let args = printf(cmn_args, vim, file)
-  " using || because this poc causes vim to exit with exitstatus != 0
   call term_sendkeys(buf, args ..
     \ '  && echo "crash 7: [OK]" >> X_crash1_result.txt' .. "\<cr>")
   call TermWait(buf, 1000)

src/testdir/test_usercommands.vim

@@ -772,6 +772,33 @@ func Test_usercmd_with_block()
   END
   call v9.CheckScriptFailure(lines, 'E1128:')
   delcommand BadCommand
+
+  let lines =<< trim END
+	  vim9script
+    command Cmd {
+        g:result = [1,
+        2]
+    }
+    Cmd
+  END
+  call v9.CheckScriptSuccess(lines)
+  call assert_equal([1, 2], g:result)
+  delcommand Cmd
+	unlet! g:result
+
+  let lines =<< trim END
+		vim9script
+		command Cmd {
+			g:result = and(0x80,
+			0x80)
+    }
+    Cmd
+  END
+  call v9.CheckScriptSuccess(lines)
+  call assert_equal(128, g:result)
+  delcommand Cmd
+	unlet! g:result
+
 endfunc
 
 func Test_delcommand_buffer()