Make it clear that the cc_tests aren't actually tests.

They should perhaps be cc_binary instead, though cc_test makes it clear
we don't want to actually ship them on the device. So just mark them as
not being gtests.

Test: treehugger
Change-Id: Iad72813748b937a5f6f96673954ed0381c3f37d5
diff --git a/Android.bp b/Android.bp
index a274618..72375ff 100644
--- a/Android.bp
+++ b/Android.bp
@@ -386,6 +386,7 @@
         "-Wall",
         "-Werror",
     ],
+    gtest: false,
     srcs: ["test/decoder/main.c"],
     static_libs: ["libhevcdec"],
     target: {
@@ -759,6 +760,7 @@
         "-Wall",
         "-Werror",
     ],
+    gtest: false,
     srcs: ["test/encoder/main.c"],
     static_libs: ["libhevcenc"],
     sanitize: {