[Coroutines] Add an O(n) algorithm for computing the cross suspend point

information.

Fixed https://github.com/llvm/llvm-project/issues/62348

Propagate cross suspend point information by visiting CFG.

Just only go through two times at most, you can get all the cross
suspend point information.

Before the patch:

```
n: 20000
4.31user 0.11system 0:04.44elapsed 99%CPU (0avgtext+0avgdata
552352maxresident)k
0inputs+8848outputs (0major+126254minor)pagefaults 0swaps

n: 40000
11.24user 0.40system 0:11.66elapsed 99%CPU (0avgtext+0avgdata
1788404maxresident)k
0inputs+17600outputs (0major+431105minor)pagefaults 0swaps

n: 60000
21.65user 0.96system 0:22.62elapsed 99%CPU (0avgtext+0avgdata
3809836maxresident)k
0inputs+26352outputs (0major+934749minor)pagefaults 0swaps

n: 80000
37.05user 1.53system 0:38.58elapsed 99%CPU (0avgtext+0avgdata
6602396maxresident)k
0inputs+35096outputs (0major+1622584minor)pagefaults 0swaps

n: 100000
51.87user 2.67system 0:54.54elapsed 99%CPU (0avgtext+0avgdata
10210736maxresident)k
0inputs+43848outputs (0major+2518945minor)pagefaults 0swaps

```
After the patch:

```
n: 20000
3.17user 0.16system 0:03.33elapsed 100%CPU (0avgtext+0avgdata
551736maxresident)k
0inputs+8848outputs (0major+126192minor)pagefaults 0swaps

n: 40000
6.10user 0.42system 0:06.54elapsed 99%CPU (0avgtext+0avgdata
1787848maxresident)k
0inputs+17600outputs (0major+432212minor)pagefaults 0swaps

n: 60000
9.13user 0.89system 0:10.03elapsed 99%CPU (0avgtext+0avgdata
3809108maxresident)k
0inputs+26352outputs (0major+931280minor)pagefaults 0swaps

n: 80000
12.44user 1.57system 0:14.02elapsed 99%CPU (0avgtext+0avgdata
6603432maxresident)k
0inputs+35096outputs (0major+1624635minor)pagefaults 0swaps

n: 100000
16.29user 2.28system 0:18.59elapsed 99%CPU (0avgtext+0avgdata
10212808maxresident)k
0inputs+43848outputs (0major+2522200minor)pagefaults 0swaps

```

Reviewed By: ChuanqiXu

Differential Revision: https://reviews.llvm.org/D154695