Acting RZMS subsemigroups over non-IsPermGroup

[wilfwilson]

Currently, subsemigroups of regular Rees 0-matrix semigroups over groups are acting semigroups, even if the group isn't an IsPermGroup group.

Either this should only be the case for perm groups, or there are some missing methods.

Here's an example of how things go wrong over other groups:

gap> G := AllSmallGroups(8)[3];
gap> R := ReesZeroMatrixSemigroup(G, [[G.1, 0, 0], [0, G.1, 0], [0, 0, G.1]]);
gap> S := Semigroup(RMSElement(R, 1, One(G), 2), RMSElement(R, 2, One(G), 1));
gap> IsPcGroup(G) and IsActingSemigroup(S);
true
gap> Size(S);
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `NrMovedPoints' on 1 arguments at /Users/Wilf/GAP/lib/methsel2.g:241 called from
NrMovedPoints( UnderlyingSemigroup( parent )
 ) at /Users/Wilf/GAP/pkg/semigroups/gap/main/setup.gi:486 called from
LambdaRank( s )( o[scc[1]]
 ) at /Users/Wilf/GAP/pkg/semigroups/gap/main/lambda-rho.gi:208 called from
LambdaOrbSchutzGp( o, m
 ); at /Users/Wilf/GAP/pkg/semigroups/gap/main/lambda-rho.gi:284 called from
LambdaOrbStabChain( o, m
 ) at /Users/Wilf/GAP/pkg/semigroups/gap/main/acting.gi:597 called from
Enumerate( SemigroupData( S ), infinity, ReturnFalse
 ) at /Users/Wilf/GAP/pkg/semigroups/gap/main/acting.gi:314 called from
...

[wilfwilson]

Resolved by PR #337