testsuite: clean up main folder

tests/Makefile.am

tests/decision_rules/example1_use_dll.mod

...imulations/multiple_lead_lags/ramst_augmented_histval.mod

tests/dsge_base2.mod

tests/equation_tags/example1_with_tags.mod

tests/equation_tags/ramst_static_tag.mod

tests/equation_tags/ramst_static_tag_block.mod

tests/estimation/estim_param_in_shock_value_xfail.mod

tests/example1.mod

tests/first_order/+matlab/+namespace/y_k.m

tests/first_order/walsh.mod

tests/forecast/example1_varexo_det.mod

tests/log_transform/ramst.mod

tests/objectives/sgu_ex1.mat

tests/objectives/sgu_ex1.mod

tests/preprocessor_checks/comments.mod

tests/preprocessor_checks/example1_extra_exo_xfail.mod

tests/preprocessor_checks/example1_mlv.mod

tests/preprocessor_checks/example1_undeclared_vars_xfail.mod

...s/preprocessor_checks/ramst_all_values_required_xfail.mod