Micro-optimize SUNMatrixWrapper::transpose (#1439)
Micro-optimize SUNMatrixWrapper::transpose (#1439)

Quick test with a large model (nx=3665) shows up to 20% reduction in cpu_time and cpu_timeB
FFroehlich/AMICI,FFroehlich/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,FFroehlich/AMICI,FFroehlich/AMICI