Add llvm-isel-fuzzer to test/CMakeLists.txt

Tests were added that depend on llvm-isel-fuzzer in r312427, so the tests
should depend on the tool.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312433 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed