inserting non-algebraic kernels

[Qian Yun]

[sin x for x in 1..10^4];

For fricas-1.3.13, it takes 15s, after recent optimizations,
it takes 7s.

But for non-algebraic kernels, we can do better.

For Expression Integer, (not EXPR EXPR INT), when the kernel
is not algebraic, its representation is canonical.

Thus, when inserting a non-algebraic new kernel, if the binary
search returns no match, then we are sure it is a new kernel,
we can insert it directly without the need to do linear search.

The above analysis is sound, right?

- Qian