[GR-29706] Skips patches when the ruby home is not set

PullRequest: truffleruby/2452

Author: eregon

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -576,9 +576,10 @@ private ConcurrentMap<String, Boolean> initializePatching(RubyContext context) {
         defineModule(truffleModule, "Patching");
         final ConcurrentMap<String, Boolean> patchFiles = new ConcurrentHashMap<>();
 
-        if (context.getOptions().PATCHING) {
+        final String rubyHome = context.getRubyHome();
+        if (context.getOptions().PATCHING && rubyHome != null) {
             try {
-                final Path patchesDirectory = Paths.get(context.getRubyHome(), "lib", "patches");
+                final Path patchesDirectory = Paths.get(rubyHome, "lib", "patches");
                 Files.walkFileTree(
                         patchesDirectory,
                         new SimpleFileVisitor<Path>() {