Revert "[SCEV] Factor out part of wrap flag detection logic [NFC-ish]"
This reverts commit 1ec6e1eb8a084bffae8a40236eb9925d8026dd07.
This change causes a significant compile-time regression:
I assume that this is due to the non-NFC part of the change, which
now performs expensive nowrap inference even for nowrap flags that
are not used by the particular code.