[c] Reverse Reachability keeps failing with out of memory errors

Reproducible with glibc repo.

```
Slicing the atom for reachables. This might take a few minutes ...
Collecting additional slices with Reverse Reachability.
Failure: java.lang.OutOfMemoryError
java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:501)
java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:485)
java.base/java.util.concurrent.ForkJoinTask.getException(ForkJoinTask.java:557)
java.base/java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:573)
java.base/java.util.concurrent.ForkJoinTask.join(ForkJoinTask.java:663)
java.base/java.util.concurrent.ForkJoinPool.invoke(ForkJoinPool.java:3123)
io.appthreat.dataflowengineoss.queryengine.SourcesToStartingPoints$.sourceTravsToStartingPoints(SourcesToStartingPoints.scala:26)
io.appthreat.dataflowengineoss.language.ExtendedCfgNode$.reachableByFlows$extension(ExtendedCfgNode.scala:54)
io.appthreat.atom.slicing.ReachableSlicing$.collectCDefaultFlows(ReachableSlicing.scala:299)
io.appthreat.atom.slicing.ReachableSlicing$.collectCLanguageFlows(ReachableSlicing.scala:267)
io.appthreat.atom.slicing.ReachableSlicing$.collectLanguageSpecificFlows(ReachableSlicing.scala:165)
io.appthreat.atom.slicing.ReachableSlicing$.collectFlowSlices(ReachableSlicing.scala:109)
io.appthreat.atom.slicing.ReachableSlicing$.calculateReachableSliceAndPersist(ReachableSlicing.scala:63)
io.appthreat.atom.Atom$.generateReachablesSlice(Atom.scala:510)
io.appthreat.atom.Atom$.generateSlice(Atom.scala:392)
io.appthreat.atom.Atom$.generateForLanguage$$anonfun$2(Atom.scala:602)
scala.util.Either.flatMap(Either.scala:360)
io.appthreat.atom.Atom$.generateForLanguage(Atom.scala:601)
io.appthreat.atom.Atom$.generateAtom(Atom.scala:585)
```