[CMake] Remove asan from runtimes test dependencies

[phosek]

Summary

asan is being built as part of the runtimes, so it shouldn't be
a dependency of runtimes test targets since this dependency won't
be satisfied after we have built the runtimes.

[phosek]

This should fix the build error introduced in D33048.

[phosek]

Already fixed in r307605.

runtimes/CMakeLists.txt

if(LLVM_INCLUDE_TESTS)
           count
           llvm-nm
           llvm-objdump
           llvm-xray
           not
           obj2yaml
           sancov
           sanstats
-          asan
         )
       foreach(target ${test_targets} ${SUB_COMPONENT_CHECK_TARGETS})
         add_dependencies(${target} ${RUNTIMES_TEST_DEPENDS})
       endforeach()
     endif()
   endif()
 endif()