Upgrade OpenBLAS to 0.3.21

[termoshtt]

Release note of OpenBLAS 0.3.21 is
https://github.com/xianyi/OpenBLAS/releases/tag/v0.3.21

[termoshtt]

when no Fortran compiler is available, OpenBLAS builds will now automatically
build LAPACK from an f2c-converted copy of LAPACK 3.9.0 unless the NO_LAPACK option
is specified (more recent releases make too heavy use of Fortran90+ features to be easily convertible to C)

openblas-build has to change the behavior around it.

[termoshtt]

Currently, openblas-build checks libopenblas.so contains LAPACK symbols because OpenBLAS build system had not built Fortran-based LAPACK routines even if NO_LAPACK is not set. On 0.3.21 this situation never happens since it builds F2C-converted routines if Fortran compiler not found unless NO_LAPACK=1. We can drop this symbol detection after updating to 0.3.21, but it will be another PR.