Add MIPS32 big-endian shellcode test

test_shellcode.py only exercised little-endian MIPS. Add a big-endian
counterpart (MIPS32EB_LIN) so MIPS BE emulation is covered too.

The shellcode is the byte-swapped form of MIPS32EL_LIN (instruction words
reversed, '/bin/sh' string left intact) and is run with endian=QL_ENDIAN.EB,
reusing the existing graceful_execve EXIT hook to end emulation cleanly.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: retrocpugeek

tests/test_shellcode.py

@@ -9,7 +9,7 @@
 sys.path.append("..")
 
 from qiling import Qiling
-from qiling.const import QL_ARCH, QL_OS, QL_INTERCEPT, QL_VERBOSE
+from qiling.const import QL_ARCH, QL_OS, QL_ENDIAN, QL_INTERCEPT, QL_VERBOSE
 
 
 # test = bytes.fromhex('cccc')
@@ -22,6 +22,13 @@
     2f7368
 ''')
 
+# big-endian counterpart of MIPS32EL_LIN: the instruction words are byte-swapped
+# while the trailing '/bin/sh' string is left as-is
+MIPS32EB_LIN = bytes.fromhex('''
+    2806ffff04d0ffff2805ffff27e410012484f00f24020fab0101010c2f62696e
+    2f7368
+''')
+
 X86_WIN = bytes.fromhex('''
     fce8820000006089e531c0648b50308b520c8b52148b72280fb74a2631ffac3c
     617c022c20c1cf0d01c7e2f252578b52108b4a3c8b4c1178e34801d1518b5920
@@ -105,6 +112,13 @@ def test_linux_mips32(self):
         ql.os.set_syscall('execve', graceful_execve, QL_INTERCEPT.EXIT)
         ql.run()
 
+    def test_linux_mips32eb(self):
+        print("Linux MIPS 32bit EB Shellcode")
+        ql = Qiling(code=MIPS32EB_LIN, archtype=QL_ARCH.MIPS, ostype=QL_OS.LINUX, endian=QL_ENDIAN.EB, verbose=QL_VERBOSE.OFF)
+
+        ql.os.set_syscall('execve', graceful_execve, QL_INTERCEPT.EXIT)
+        ql.run()
+
     # This shellcode needs to be changed to something non-blocking
     def test_linux_arm(self):
         print("Linux ARM 32bit Shellcode")