stdscript: Add v0 stake revoke p2sh benchmark.

BenchmarkIsStakeRevocationScriptHashScript
------------------------------------------
v0_complex_non_standard   725635868   1.631 ns/op   0 allocs/op
v0_stake_revoke_p2sh      522431919   2.571 ns/op   0 allocs/op

This is part of a series of commits to fully implement the stdscript
package.

internal/staging/stdscript/script_bench_test.go

@@ -242,3 +242,13 @@ func BenchmarkIsStakeRevocationPubKeyHashScript(b *testing.B) {
 	}
 	benchIsX(b, filterFn, IsStakeRevocationPubKeyHashScript)
 }
+
+// BenchmarkIsStakeRevocationScriptHashScript benchmarks the performance of
+// various public key scripts to determine if they are stake revocation p2sh
+// scripts.
+func BenchmarkIsStakeRevocationScriptHashScript(b *testing.B) {
+	filterFn := func(test scriptTest) bool {
+		return test.wantType == STStakeRevocationScriptHash
+	}
+	benchIsX(b, filterFn, IsStakeRevocationScriptHashScript)
+}