Related to Dynare/dynare#1840

This is made necessary by commit dd1ec10e.

Either ensure that oo_.determinstic_simulation.status is set, or really error out.

Was incorrectly using solve_tolf.

We were previously using version 1.8.

The default of options_.slowc is already 1.

The “all” rule being equivalent to the “build” rule, juste delete the former
and move the latter upwards.

If solved function returns complex values (with nonzero imaginary part), turn
them into NaNs. This mimics the behaviour of the use_dll case.

Next step will be to adapt the trust region algorithm to diminish radius when
there are NaNs.

Incidentally, bump the required GCC version to 9, since we use the %re and %im
components of complex values in Fortran.

Note that the unitary test in lyapunov_solver.m that checks sparse matrix input
had to be removed. Previously, this test was passing by chance (because the
sparse test matrices had actually no zero element, hence the internal double
float storage was the same as in the dense case). Now it consistently fails
with the additional checks in disclyap_fast MEX.

Improve the model that is used to test all combinations of algorithms with
block and bytecode options, by ensuring that it includes the 8 possible types of blocks:
– Solve {forward, backward, two boundaries} {simple, complete}
– Evaluate {forward, backward}

All the “Solve” blocks are also included in both linear and nonlinear forms
(since the codepaths are typically different depending on the linearity of
the block).

Note that there is no such thing as a nonlinear “Evaluate” block, since the
endogenous variables of the block always enter linearly (on the LHS).

Also:
- use perfect_foresight_{setup,solver} instead of simul (and disable automatic homotopy)
- add a shock on e_R (though this is not strictly needed since the
  corresponding block already inherits the shock from another ancestor block)
- remove the block for observables, there is already another block of type
  “Evaluate forward”

This commit makes it closer to the implementation in bytecode. In practice,
this change fixes convergence problems on some models.

Manual: clarify potential naming issues in steady state files

See merge request Dynare/dynare!2007

Bytecode: fix stack_solve_algo=4 when a “solve backward/forward” block follows a “solve two boundaries” block

When solving a “Solve two boundarise” block with stack_solve_algo=4, the
“slowc” variable is modified. This would affect the resolution of further
“solve backward/forward” blocks, which would yield results.

The fix consists in saving and restoring “slowc”.

posterior moments: fix bugs that cause crashes

See merge request Dynare/dynare!2006

- Delete non-existing output argument
- prevent info from being overwritten

When jacobian is evaluated numerically.

When the Newton fails in the simulation of backward models.

Return the paths for the endogenous only before the nonlinear solver crash.

Can be useful when writing “z = resid;” in a .mod file (i.e. not using the
preprocessor syntax).

When this option is given, the “resid” command only displays non-zero residuals

Only one iteration is performed on linear blocks. But in the case of
stack_solve_algo=4 it is not enough, since it will not find the right optimal
path lenght at the first iteration (even though that optimal path length is
ufnitary).

There were various issues with the construction of sparse submatrices.

By the way, refactor and document the code to make it more readable.