optimze 3g file creation with test case

Author: JacobBarthelmeh

.github/workflows/sftp-test.yml

@@ -179,12 +179,14 @@ jobs:
         working-directory: ./wolfssh/
         run: make
 
-      - name: Create 3GB random test file
+      - name: Create 3GB test file
         working-directory: ./wolfssh/
         run: |
-          dd if=/dev/urandom of=large_test.dat bs=1M count=3072
+          dd if=/dev/urandom of=seed.dat bs=1M count=10
+          for i in $(seq 1 308); do cat seed.dat >> large_test.dat; done
+          rm seed.dat
           sha256sum large_test.dat > large_test.dat.sha256
-          echo "Created 3GB random file, SHA-256: $(cat large_test.dat.sha256)"
+          echo "Created 3GB test file, SHA-256: $(cat large_test.dat.sha256)"
 
       - name: Start echoserver
         working-directory: ./wolfssh/