memory leak

Nobody has claimed this yet.

This code

```
engineMemory = value Core#"private dictionary"#"engineMemory"
needsPackage "RandomCanonicalCurves"
ps = () -> run ( "ps u " | toString processID () )
leak = c -> (
setRandomSeed "37862873";
g := 9;
p := 12347;
numEx := 40;
T := ZZ/p[t_0..t_(g-1)];
for i from 1 to 100 do (
IC := (random canonicalCurve)(g,T);
minimalBetti IC;
-- registerFinalizer (IC.cache.quotient,"--");
if c then IC.cache.quotient = null;
<< "." << flush;);
collectGarbage();
print engineMemory();
)
ps()
leak true
ps()
leak false
ps()
```

runnning under
https://github.com/mikestillman/M2/tree/newres
produces this totally perplexing result:

```
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
dan 75775 0.0 0.5 2917676 85244 s002 S+ 10:39AM 9:50.42 /Users/dan/src/M2/M2-Macaula
....................................................................................................size of each slabs = 2040
total engine space allocated = 0k
stash k total k in use size nalloc inuse highwater freed
Finalizations of new resolutions:
# of res objects constructed/deconstructed=(100,100) #left = 0
# of res objects constructed/deconstructed=(100,100) #left = 0

USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
dan 75775 102.8 0.6 2932208 101080 s002 S+ 10:39AM 10:59.57 /Users/dan/src/M2/M2-Macaula
....................................................................................................size of each slabs = 2040
total engine space allocated = 0k
stash k total k in use size nalloc inuse highwater freed
Finalizations of new resolutions:
# of res objects constructed/deconstructed=(200,180) #left = 20
# of res objects constructed/deconstructed=(200,180) #left = 20

USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
dan 75775 140.4 2.0 3177916 331080 s002 S+ 10:39AM 12:14.92 /Users/dan/src/M2/M2-Macaula
```

Solving it would improve memory performance a lot.