[hwasan] Refactor frame record info into function

This way it can be reused easily in D128387.

Note this changes the IR slightly. Before The steps for calculating and storing the frame record info were:

1. getPC
2. getSP
3. inttoptr
4. or SP, PC
5. store

Now the steps are:

1. getPC
2. getSP
3. or SP, PC
4. inttoptr
5. store

Differential Revision: https://reviews.llvm.org/D129315