[CSSPGO][Preinliner] Bump up the threshold to favor previous compiler inline decision.

The compiler has more insight and knowledge about functions based on their IR and attribures and should make a better inline decision than the offline preinliner does which is purely based on callsites hotness and code size.  Therefore I'm making changes to favor previous compiler inline decision by bumping up the callsite allowance.

This should improve the performance by more than 1% according to testing on Meta services.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D153797