Ruby: Avoid multiple RegExpEscape::getValue results

Author: hvitved

ruby/ql/lib/codeql/ruby/security/performance/RegExpTreeView.qll

@@ -405,7 +405,9 @@ class RegExpEscape extends RegExpNormalChar {
     result = this.getUnicode()
   }
 
-  predicate isIdentityEscape() { not this.getUnescaped() in ["n", "r", "t"] }
+  predicate isIdentityEscape() {
+    not this.getUnescaped() in ["n", "r", "t"] and not this.isUnicode()
+  }
 
   /**
    * Gets the text for this escape. That is e.g. "\w".

ruby/ql/test/library-tests/regexp/regexp.expected

@@ -271,4 +271,3 @@ regExpNormalCharValue
 | regexp.rb:72:17:72:17 | f | f |
 | regexp.rb:79:2:79:4 | abc | abc |
 | regexp.rb:82:2:82:7 | \\u{987 | \u0987 |
-| regexp.rb:82:2:82:7 | \\u{987 | u{987 |