Codec2: pass block pools by ID

This highlighted a cfi bug so disabled cfi:

frameworks/av/media/libstagefright/codecs/avcdec/C2SoftAvcDec.cpp:1237:15: runtime error:
control flow integrity check for type 'android::C2BlockPool' failed during virtual call
(vtable address 0x0078b2f659c0)
0x0078b2f659c0: note: invalid vtable in module /system/lib64/libstagefright_soft_c2avcdec.so
 00 00 00 00  98 a8 ef b2 78 00 00 00  f0 df f3 b2 78 00 00 00  00 e0 f3 b2 78 00 00 00  00 e0 f3 b2
              ^

Bug: 64121714
Test: unittest
Change-Id: I25d9c9d603e78c5043568cfb951d26aacea798a4