Now that `CHECK_{BLAS,LAPACK}_LIBRARIES` are functions, we can set
`CMAKE_FIND_LIBRARY_SUFFIXES` locally without affecting the global
state.  This avoids the need for local state switching that was added in
commit 9ef82d95 (FindBLAS: Fix detection of OpenMP as dependency of
BLA_STATIC, 2021-04-07, v3.20.1~3^2), so remove that.