Attempt to reduce flakiness in workingset-samples.cpp
Attempt to reduce flakiness in workingset-samples.cpp

The test is matching against 'KB' but it looks like the output can be
'MB'.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@274587 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