Contracts move fixtures to new crate (#2246)

Small PR that introduce a new crate that will host RISC-V & wasm
fixtures for testing pallet-contracts

substrate/frame/contracts/fixtures/data/set_code_hash.wat

@@ -0,0 +1,43 @@
+(module
+	(import "seal0" "seal_input" (func $seal_input (param i32 i32)))
+	(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
+	(import "seal0" "seal_set_code_hash" (func $seal_set_code_hash (param i32) (result i32)))
+
+	(import "env" "memory" (memory 1 1))
+
+	;; [0, 32) here we store input
+
+	;; [32, 36) input size
+	(data (i32.const 32) "\20")
+
+	;; [36, 40) return value
+	(data (i32.const 36) "\01")
+
+	(func $assert (param i32)
+		(block $ok
+			(br_if $ok
+				(get_local 0)
+			)
+			(unreachable)
+		)
+	)
+
+	(func (export "call")
+		(local $exit_code i32)
+
+		(call $seal_input (i32.const 0) (i32.const 32))
+
+		(set_local $exit_code
+			(call $seal_set_code_hash (i32.const 0)) ;; Pointer to the input data.
+		)
+		(call $assert
+			(i32.eq (get_local $exit_code) (i32.const 0)) ;; ReturnCode::Success
+		)
+
+		;; we return 1 after setting new code_hash
+		;; next `call` will NOT return this value, because contract code has been changed
+		(call $seal_return (i32.const 0) (i32.const 36) (i32.const 4))
+	)
+
+	(func (export "deploy"))
+)