message: Explicitly specify "default" android_sdk_proguard_config for redex tests
  Summary:
  An upcoming buck PR (D5596384) will (may?) require this to be
  explicitly specified, and these tests require the default PG config.  Even if
  said PR doesn't go in in its current form, this change won't hurt.
diff: @@ -35,6 +35,7 @@ def redex_instr_test(
  android_binary(
  name = name + '_non_redex',
  + android_sdk_proguard_config = "default",
  manifest = '%s:AndroidManifest.xml' % REDEX_INSTR_ROOT,
  keystore = '//keystores:prod',
  package_type = 'release',
  @@ -52,6 +53,7 @@ def redex_instr_test(
  android_binary(
  name = android_binary_name,
  + android_sdk_proguard_config = "default",
  manifest = '%s:AndroidManifest.xml' % REDEX_INSTR_ROOT,
  keystore = '//keystores:prod',
  package_type = 'release',
  