[libFuzzer] Increase the iteration limit in shrink.test
[libFuzzer] Increase the iteration limit in shrink.test

After https://reviews.llvm.org/D48800, shrink.test started failing on
x86_64h architecture.
Looking into this, the optimization pass is too eager to unroll the loop
on x86_64h, possibly leading to worse coverage data.

Alternative solutions include not unrolling the loop when fuzzing, or
disabling this test on that architecture.

Differential Revision: https://reviews.llvm.org/D50484

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@339303 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt