vppinfra: fix bihash test-debug aarch64 sporadic failure

Turns out that both the multi-core and single-core add / del tests run
for just under 5 seconds (aarch64, debug image). Increase the vapi =>
debug CLI timeout to avoid spurious failures.

Type: test

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: Ia64bffa82a908172a21c34f3ae4402ad774af28a

src/vppinfra/test/test_bihash.py

@@ -11,6 +11,9 @@ class TestBihash(VppTestCase):
 
     @classmethod
     def setUpClass(cls):
+        # increase vapi timeout, to avoid spurious "test bihash ..."
+        # failures reported on aarch64 w/ test-debug
+        cls.vapi_response_timeout = 20
         super(TestBihash, cls).setUpClass()
 
     @classmethod