More robust check for stopping at previously determined EOF

Co-authored-by: Devin Nusbaum <dwnusbaum@users.noreply.github.com>

Author: das7pad

src/main/java/org/jenkinsci/plugins/workflow/log/FileLogStorage.java

@@ -465,7 +465,7 @@ public int read(@NonNull byte[] b) throws IOException {
 
             @Override
             public int read(@NonNull byte[] b, int off, int len) throws IOException {
-                if (stepLogPos == stepLogSize) {
+                if (stepLogPos >= stepLogSize) {
                     return -1;
                 }
                 ensureOpen();