alarm sometimes not caught

Nobody has claimed this yet.

Sometimes an alarm is not caught. Mike has reported this, and his just occurred under Debian 10 while testing the Matroids package, which uses a 2 second alarm to implement a "quick" test. I can't reproduce it.
```
i1 : --/home/dan/src/M2/M2/Macaulay2/packages/Matroids.m2:3655: location of test code

M0 = matroid graph({{a,b},{b,c},{c,d},{d,e},{e,f},{f,g},{f,h},{c,h},{c,f},{a,g},{d,g}})

o1 = a matroid of rank 7 on 11 elements

o1 : Matroid

i2 : M1 = matroid graph({{a,b},{b,c},{c,d},{d,e},{e,f},{f,g},{f,h},{c,h},{c,f},{a,g},{a,h}})

o2 = a matroid of rank 7 on 11 elements

o2 : Matroid

i3 : T = ZZ[x,y]

o3 = T

o3 : PolynomialRing

i4 : assert(isWellDefined M0 and isWellDefined M1)

i5 : assert(tuttePolynomial(M0, T) === tuttePolynomial(M1, T))

i6 : F1 = set{0,1,2,3,7}

o6 = set {0, 1, 2, 3, 7}

o6 : Set

i7 : F2 = F1 + set{5,8}

o7 = set {0, 1, 2, 3, 5, 7, 8}

o7 : Set

i8 : assert(areIsomorphic(uniformMatroid(2,2), minor(M0, F1, M0.groundSet - F2)))

i9 : assert(areIsomorphic(M0, matroid graph edges graph M0_*))
Alarm clock
```

Start by reproducing the Matroids package test at Matroids.m2:3655 under Debian 10, using the reported two-second alarm. Compare runs where the alarm is caught with the shown "Alarm clock" failure and trace the relevant alarm handling entry point. Done means the test alarm is reliably caught without the reported failure.

Written by the indexing model from the issue text.