Fix a -Wbitwise-conditional-parentheses warning in _LIBUNWIND_ARM_EHABI libunwind builds

```
src/UnwindCursor.hpp:1344:51: error: operator '?:' has lower precedence than '|';
    '|' will be evaluated first [-Werror,-Wbitwise-conditional-parentheses]
  _info.flags = isSingleWordEHT ? 1 : 0 | scope32 ? 0x2 : 0;  // Use enum?
                                      ~~~~~~~~~~~ ^
src/UnwindCursor.hpp:1344:51: note: place parentheses around the '|' expression
    to silence this warning
  _info.flags = isSingleWordEHT ? 1 : 0 | scope32 ? 0x2 : 0;  // Use enum?
                                                  ^
                                      (          )
src/UnwindCursor.hpp:1344:51: note: place parentheses around the '?:' expression
    to evaluate it first
  _info.flags = isSingleWordEHT ? 1 : 0 | scope32 ? 0x2 : 0;  // Use enum?
                                                  ^
                                          (                )
```

But `0 |` is a no-op for either of those two interpretati...