### Godot version

4.0 beta17

### System information

Windows10

### Issue description

call `"".split()`
Is there an infinite loop inside? Function does not return.

### Steps to reproduce

"".split()

### Minimal reproduction project

N/A
resize(p_length + 1);
	char32_t *dst = ptrw();
	dst[p_length] = 0;
	for (int i = 0; i < p_length; i++) {
		if (p_char[i] == 0) {
			print_unicode_error("NUL character", true);
			dst[i] = 0x20;
			continue;
		}
		if ((p_char[i] & 0xfffff800) == 0xd800) {
			print_unicode_error(vformat("Unpaired surrogate (%x)", (uint32_t)p_char[i]));
		}
		if (p_char[i] > 0x10ffff) {
			print_unicode_error(vformat("Invalid unicode codepoint (%x)", (uint32_t)p_char[i]));
		}
		dst[i] = p_char[i];
	}
}
void String::operator=(const char *p_str) {
	copy_from(p_str);
}
void String::operator=(const char32_t *p_str) {
	copy_from(p_str);
}
void String::operator=(const wchar_t *p_str) {