tests/sizeof_tcb: fix test condition

Fix test condition to match size if compiled with
    and w/o DEVELHELP.

tests/sizeof_tcb/tests/01-run.py

@@ -12,7 +12,7 @@ import sys
 
 def testfunc(child):
     child.expect_exact('\tmember, sizeof, offsetof')
-    child.expect_exact('sizeof(thread_t): 36')
+    child.expect(r'sizeof\(thread_t\): [36, 48]')
     child.expect_exact('\tsp            4   0')
     child.expect_exact('\tstatus        1   4')
     child.expect_exact('\tpriority      1   5')