Make traced a top-level executable

- Make a little change to the Android blueprint generator, which
  makes it so that executables in the top-level BUILD.gn file
  don't get the perfetto_ prefix. This allows to get a binary
  in the Android.bp that is called just "traced" and ends up in
  /system/bin/traced
- Adds the consumer_cmd binary introduced by the previous change
  (Iccf88b7b1d2beb6a0750adafd86d92a0f563182d) to the blueprint.

Bug:
Change-Id: Ia091ba35f186a451c4c0e111fcc03a0d8decf816
diff --git a/tools/gen_android_bp b/tools/gen_android_bp
index eb5e051..bcc0f43 100755
--- a/tools/gen_android_bp
+++ b/tools/gen_android_bp
@@ -34,7 +34,11 @@
 import sys
 
 # Default targets to translate to the blueprint file.
-default_targets = ['//:perfetto_tests', '//src/traced:traced']
+default_targets = [
+    '//:perfetto_tests',
+    '//:traced',
+    '//src/tracing:consumer_cmd',
+]
 
 # Arguments for the GN output directory.
 gn_args = 'target_os="android" target_cpu="arm" is_debug=false'
@@ -195,9 +199,9 @@
 
 def label_to_module_name(label):
     """Turn a GN label (e.g., //:perfetto_tests) into a module name."""
-    label = re.sub(r'^//:?', '', label)
-    module = re.sub(r'[^a-zA-Z0-9_]', '_', label)
-    if not module.startswith(module_prefix):
+    module = re.sub(r'^//:?', '', label)
+    module = re.sub(r'[^a-zA-Z0-9_]', '_', module)
+    if not module.startswith(module_prefix) and label not in default_targets:
         return module_prefix + module
     return module