EIP 145: Bitwise shifting instructions in EVM (#8451)

* Add SHL, SHR, SAR opcodes

* Add have_bitwise_shifting schedule flag

* Add all EIP tests for SHL

* Add SHR implementation and tests

* Implement SAR and add tests

* Add eip145transition config param

* Change map_or to map_or_else when possible

ethcore/vm/src/tests.rs

@@ -88,6 +88,13 @@ impl FakeExt {
 		ext
 	}
 
+	/// New fake externalities with constantinople schedule rules
+	pub fn new_constantinople() -> Self {
+		let mut ext = FakeExt::default();
+		ext.schedule = Schedule::new_constantinople();
+		ext
+	}
+
 	/// Alter fake externalities to allow wasm
 	pub fn with_wasm(mut self) -> Self {
 		self.schedule.wasm = Some(Default::default());