another timeout+outofmem for primdecGTZ() and minAssGTZ()

[jakobkroeker]

(simplified /infiniteTests/log/test.minAssGTZ.nomp.minimize.02/bugs/id_3.18.outofmem.bug)

LIB("primdec.lib");
ring rng = (0),(x,y,z),(dp);

ideal I = x*y+x^4-1,x*y^2*z+x^2*z-1;
option(prot);
def result= primdecSY(I); //OK
result= primdecGTZ(I); // timeout+outofmem, hangs at `inew=quotient(iold,@f);`
// finishes with modifications - see branch `spielwiese.testmode.mod`
// that is suspicious: why after the modifications (some std calls replaced by 'groebner' calls
the command `inew=quotient(iold,@f);` does not hang anymore?

> result;
[1]:
   [1]:
      _[1]=x3-y2z-xz+y
      _[2]=xy2z+x2z-1
      _[3]=y4z2-y3z-x2z2-xyz-x2+2z
   [2]:
      _[1]=x3-y2z-xz+y
      _[2]=xy2z+x2z-1
      _[3]=y4z2-y3z-x2z2-xyz-x2+2z

[jakobkroeker]

another example (taken from test.minAssGTZ.nomp.minimize.02/bugs/id_3.19.outofmem.bug)

LIB("primdec.lib");
ring rng = (0),(x,y,z),(dp);
ideal I = x^2*z-x*y^3-1,-x^4+x*z^2-y^2*z^2;
def result= minAssChar(I);
result;
option(prot);
result= minAssGTZ(I);