[Pipeline] Adjust PostOrderFunctionAttrs placement in simplification pipeline

[Pipeline] Adjust PostOrderFunctionAttrs placement in simplification pipeline

We can infer more attribute information once functions are fully
simplified, so move the PostOrderFunctionAttrs pass after the function
simplification pipeline. However, just doing this can impact
simplification of recursive functions since function simplification
takes advantage of function attributes of callees (some LLVM tests are
actually impacted by this), so keep a copy of PostOrderFunctionAttrs
before the function simplification pipeline that only runs on recursive
functions.

For example, this fixes the small regression noticed in https://reviews.llvm.org/D128830.

This requires some restructuring of the CGSCC NoRerun feature. We need
to cache the ShouldNotRunFunctionPassesAnalysis analysis after the
simplification is done, which now is after the second
PostOrderFunctionAttrs run, rather than after the function
simplification pipeline.

Compile time impact:
https://llvm-compile-time-tracker.com/compare.php?from=33cf40122279342b50f92a3a53f5c185390b6018&to=1bb2a07875634e508a6bdf2ca1b130f55510f060&stat=instructions:u

Compile time increase from unconditionally running the first PostOrderFunctionAttrs:
https://llvm-compile-time-tracker.com/compare.php?from=1bb2a07875634e508a6bdf2ca1b130f55510f060&to=f4f87e89cc7a35c64e3a103a8036192a84ae002b&stat=instructions:u

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D145210