Add janitors to the OWNERS file am: c2a99c4cbd

Original change: https://android-review.googlesource.com/c/platform/external/dlmalloc/+/3423628

Change-Id: I2db9abc615b6f357bcaab716c7df0fac107792c4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>