[AggressiveInstCombine] Inline strcmp/strncmp (#89371)

Inline calls to strcmp(s1, s2) and strncmp(s1, s2, N), where N and
exactly one of s1 and s2 are constant.

For example:

```c
int res = strcmp(s, "ab");
```

is converted to

```c
int res = (int)s[0] - (int)'a';
if (res != 0)
  goto END;
res = (int)s[1] - (int)'b';
if (res != 0)
  goto END;
res = (int)s[2] - (int)'\0';
END:
```

Ported from a similar gcc feature [Inline strcmp with small constant
strings](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78809).