Add positive and negative tests and test runner for Zap encoder sanitizer

Author: danielriddell21

go/ql/tests/LogInjectionSanitizer/positive.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	userInput := readUser() // source: tainted
+	fmt.Println(userInput) // sink: logging/printing (should be flagged by a positive test)
+}
+
+func readUser() string { return "line\ninjection" }