Add tools/lsan/suppressions.txt
Add tools/lsan/suppressions.txt

The new buildbots are using the default config
for ASan, which has Leak Sanitizer (LSan) enabled.
This assumes a suppression file exists in this
location.

TBR=fbarchard@google.com
TESTED=Passing linux_asan trybot run.
BUG=

Review URL: https://webrtc-codereview.appspot.com/27589004

git-svn-id: a51711482b6ba0e1d1ab095578a045eeae45ac9a@1091 16f28f9a-4ce2-e073-06de-1de4eb20be90

granalberto/libyuv,granalberto/libyuv,archos-sa/libyuv-avp,rig-project/libyuv,archos-sa/libyuv-avp,granalberto/libyuv,archos-sa/libyuv-avp,granalberto/libyuv,rig-project/libyuv,rig-project/libyuv