Test that backward delete behavior matches AppKit.
| Test: | é | Expected | |
| Test: | а́ | Expected | |
| Test: | วั | Expected | ว |
| Test: | ế | Expected | |
| Test: | q̣̇ | Expected | |
| Test: | q̣ | Expected | |
| Test: | شْ | Expected | ش |
| Test: | אֱ | Expected | א |
| Test: | 각 | Expected | |
| Test: | ダ | Expected | |
| Test: | ﾀﾞ | Expected | |
| Test: | 𐐀 | Expected |