Revert "Add santa-tracker benchmark app"

This reverts commit e20e0278ae1619c540c4d4b35dc4eb89bc6738d9.

Reason for revert: forgot to edit build.gradle to change benchamrk name.

Change-Id: Id6d8fb7a0ede01c2efcb43da033a31511904afda
diff --git a/build.gradle b/build.gradle
index f1abcb7..f857f9e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -347,7 +347,6 @@
 
 def x20Dependencies = [
     "third_party": [
-        "benchmarks/bench-santa-tracker-android",
         "gmail/gmail_android_170604.16",
         "gmscore/v4",
         "gmscore/v5",