Bad blocks RPC + reporting (#9433)

* Bad blocks RPC.

* Return bad blocks via RPC.

* Fix test.

* More verbose bad block message.

* Expose via CLI.

* Remove stray whitespace.

* Remove stray newline.

* Fix tests.

rpc/src/v1/traits/debug.rs

@@ -0,0 +1,30 @@
+// Copyright 2015-2018 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Debug RPC interface.
+
+use jsonrpc_core::Result;
+
+use v1::types::RichBlock;
+
+build_rpc_trait! {
+	/// Debug RPC interface.
+	pub trait Debug {
+		/// Returns recently seen bad blocks.
+		#[rpc(name = "debug_getBadBlocks")]
+		fn bad_blocks(&self) -> Result<Vec<RichBlock>>;
+	}
+}