Update git submodules

* Update system/core from branch 'master'
  to 6e6df01f3e3eadba0c0fd0b719a993539f7e2e24
  - Merge "Move cutils over to mallopt()."
  - Move cutils over to mallopt().
    
    Bug: http://b/135772972
    Test: treehugger
    Change-Id: I35e0fc657f2e4cecea2a29f78cad148895413e17
    
1 file changed