1953 defensive testing extrinsic (#1998)

# Description

The `trigger_defensive` call has been added to the `root-testing`
pallet. The idea is to have this pallet running on `Rococo/Westend` and
use it to verify if the runtime monitoring works end-to-end.

To accomplish this, `trigger_defensive` dispatches an event when it is
called.

Closes #1953

# Checklist

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"Description" section above
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  required)
- [ ] I have made corresponding changes to the documentation (if
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- [ ] I have added tests that prove my fix is effective or that my
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✄
-----------------------------------------------------------------------------

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/frame/support/src/traits/misc.rs

@@ -55,7 +55,7 @@ impl VariantCount for () {
 macro_rules! defensive {
 	() => {
 		frame_support::__private::log::error!(
-			target: "runtime",
+			target: "runtime::defensive",
 			"{}",
 			$crate::traits::DEFENSIVE_OP_PUBLIC_ERROR
 		);
@@ -63,7 +63,7 @@ macro_rules! defensive {
 	};
 	($error:expr $(,)?) => {
 		frame_support::__private::log::error!(
-			target: "runtime",
+			target: "runtime::defensive",
 			"{}: {:?}",
 			$crate::traits::DEFENSIVE_OP_PUBLIC_ERROR,
 			$error
@@ -72,7 +72,7 @@ macro_rules! defensive {
 	};
 	($error:expr, $proof:expr $(,)?) => {
 		frame_support::__private::log::error!(
-			target: "runtime",
+			target: "runtime::defensive",
 			"{}: {:?}: {:?}",
 			$crate::traits::DEFENSIVE_OP_PUBLIC_ERROR,
 			$error,