JavaScript: Ignore outDirs that would exclude everything

In #19680 we added support for automatically ignoring files in the
`outDir` directory as specified in the TSconfig compiler options (as
these files were likely duplicates of `.ts` file we were already
scanning).

However, in some cases people put `outDir: "."` or even `outDir: ".."`
in their configuration, which had the side effect of excluding _all_
files, leading to a failed extraction.

With the changes in this PR, we now ignore any `outDir`s that are not
properly contained within the source root of the code being scanned.
This should prevent the files from being extracted, while still allowing
us to not double-scan files in, say, a `.github` directory, as seen in
some Actions workflows.

javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java

@@ -754,7 +754,11 @@ public class AutoBuild {
             continue;
           }
           Path odir = cfg.getParent().resolve(root.getCompilerOptions().getOutDir()).toAbsolutePath().normalize();
-          outDirs.add(odir);
+          // Only exclude outDirs that are proper subdirectories of the source root
+          // This prevents excluding all code when outDir points outside the source root or to the source root itself
+          if (tryRelativize(LGTM_SRC, odir) != null && !odir.equals(LGTM_SRC)) {
+            outDirs.add(odir);
+          }
         }
       } catch (Exception e) {
         // ignore malformed tsconfig or missing fields