Tack location of InstallImmediateMethod

Before:

    gap> TraceImmediateMethods( );
    gap> g:= Group( (1,2,3), (1,2) );;
    #I  immediate: Size
    #I  immediate: IsCyclic
    #I  immediate: IsCommutative
    #I  immediate: IsTrivial
    gap>
    gap> M0:=Magma(FamilyObj([1]), []);;
    gap> AsSSortedList(M0);
    #I  immediate: RepresentativeSmallest
    #I  immediate: AsList
    #I  immediate: EnumeratorSorted
    #I  immediate: GeneratorsOfDomain
    #I  immediate: Size
    #I  immediate: RepresentativeSmallest
    #I  immediate: IsFinite
    #I  immediate: IsTrivial
    #I  immediate: IsEmpty
    #I  immediate: IsNonTrivial
    #I  immediate: Size
    #I  immediate: RepresentativeSmallest
    [  ]

After (note how e.g. the entry for EnumeratorSorted points at
coll.gi:379, and not at the location where the method function
was defined):

    gap> TraceImmediateMethods( );
    gap> g:= Group( (1,2,3), (1,2) );;
    #I RunImmediateMethods
    #I  immediate: Size at GAPROOT/lib/coll.gi:179
    #I  immediate: IsCyclic at GAPROOT/lib/grp.gi:40
    #I  immediate: IsCommutative at GAPROOT/lib/magma.gi:196
    #I  immediate: IsTrivial at GAPROOT/lib/magma.gi:130
    gap>
    gap> M0:=Magma(FamilyObj([1]), []);;
    #I RunImmediateMethods
    #I RunImmediateMethods
    gap> AsSSortedList(M0);
    #I RunImmediateMethods
    #I  immediate: RepresentativeSmallest at GAPROOT/lib/coll.gi:226
    #I  immediate: AsList at GAPROOT/lib/domain.gi:206
    #I  immediate: EnumeratorSorted at GAPROOT/lib/coll.gi:379
    #I  immediate: GeneratorsOfDomain at GAPROOT/lib/domain.gi:181
    #I  immediate: Size at GAPROOT/lib/coll.gi:183
    #I  immediate: RepresentativeSmallest at GAPROOT/lib/coll.gi:215
    #I  immediate: IsFinite at GAPROOT/lib/coll.gi:148
    #I  immediate: IsTrivial at GAPROOT/lib/coll.gi:116
    #I  immediate: IsEmpty at GAPROOT/lib/coll.gi:97
    #I  immediate: IsNonTrivial at GAPROOT/lib/coll.gi:134
    #I RunImmediateMethods
    #I  immediate: Size at GAPROOT/lib/coll.gi:179
    #I RunImmediateMethods
    #I  immediate: RepresentativeSmallest at GAPROOT/lib/coll.gi:215
    [  ]

Author: fingolfin