Follow-up to #30476
Found by OSS-Fuzz / https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=70780
Seems wasteful to spend time in TopUp
while fuzzing, so my recommendation would be to limit TopUp iterations a bit.
Context: clusterfuzz-testcase-scriptpubkeyman-5934021442338816.bin.txt
0$ FUZZ=scriptpubkeyman perf record -g --call-graph dwarf ./src/test/fuzz/fuzz -runs=1 ./clusterfuzz-testcase-scriptpubkeyman-5934021442338816.bin.txt
1$ hotspot ./perf.data