JS: Speed up detection of jQuery marker comments

Combine two regexes into a single one.
This saves up to 5s on large databases by reducing the number
of separate scans of the comments table before regex matching.

The combined regex is slightly more permissive than the
original two, since it allows a combination of the two
matched formats. A string that matches one of the original
regexes will match the combined regex.

Author: adityasharad

javascript/ql/lib/semmle/javascript/dependencies/FrameworkLibraries.qll

@@ -299,12 +299,15 @@ private class JQuery extends FrameworkLibraryWithGenericURL {
 private predicate jQueryMarkerComment(Comment c, TopLevel tl, string version) {
   tl = c.getTopLevel() and
   exists(string txt | txt = c.getText() |
-    // more recent versions use this format
+    // More recent versions use this format:
+    // "(?s).*jQuery (?:JavaScript Library )?v(" + versionRegex() + ").*",
+    // Earlier versions used this format:
+    // "(?s).*jQuery (" + versionRegex() + ") - New Wave Javascript.*"
+    // For efficiency, construct a single regex that matches both,
+    // at the cost of being slightly more permissive.
     version =
-      txt.regexpCapture("(?s).*jQuery (?:JavaScript Library )?v(" + versionRegex() + ").*", 1)
-    or
-    // earlier versions used this format
-    version = txt.regexpCapture("(?s).*jQuery (" + versionRegex() + ") - New Wave Javascript.*", 1)
+      txt.regexpCapture("(?s).*jQuery (?:JavaScript Library )?v?(" + versionRegex() +
+          ")(?: - New Wave Javascript)?.*", 1)
     or
     // 1.0.0 and 1.0.1 have the same marker comment; we call them both "1.0"
     txt.matches("%jQuery - New Wave Javascript%") and version = "1.0"