Cleanup C and C++ compiler flags

Cleanup the setting of C and C++ compiler flags:
 * (Almost) all compiler flags are set uniformly
   in the system/bt/Android.mk file.
 * Enable by default breaking the compilation if there is a
   compilation warning: -Werror
 * Enable most compilation warnings: -Wall -Wextra
 * Renamed Android.mk related flags:
   - bdroid_C_INCLUDES -> bluetooth_C_INCLUDES
   - bdroid_CFLAGS -> bluetooth_CFLAGS
 * Introduce variables for C-only and C++ only compiler:
   - bluetooth_CFLAGS: common C and C++ compiler flags
   - bluetooth_CONLYFLAGS: C only compiler flags
   - bluetooth_CPPFLAGS: C++ only compiler flags
 * Disable warnings for existing issues - to be removed as issues are
   resolved
 * Add a workaround for libchrome and -DNDEBUG usage.

Bug: 26879229
Change-Id: Ie7595965ca0c8ead0e95e983e76c327e7891b2c3

• Android.mk[diff]
• audio_a2dp_hw/Android.mk[diff]
• bta/Android.mk[diff]
• btcore/Android.mk[diff]
• btif/Android.mk[diff]
• conf/Android.mk[diff]
• device/Android.mk[diff]
• embdrv/Android.mk[diff]
• embdrv/sbc/Android.mk[diff]
• embdrv/sbc/decoder/Android.mk[diff]
• hci/Android.mk[diff]
• main/Android.mk[diff]
• osi/Android.mk[diff]
• profile/Android.mk[diff]
• service/Android.mk[diff]
• service/client/main.cpp[diff]
• service/example/heart_rate/server_main.cpp[diff]
• service/main.cpp[diff]
• service/test/main.cpp[diff]
• stack/Android.mk[diff]
• test/bluedroidtest/Android.mk[diff]
• test/suite/Android.mk[diff]
• tools/bdtool/Android.mk.disabled[diff]
• tools/hci/Android.mk.disabled[diff]
• utils/Android.mk[diff]
• vendor_libs/linux/Android.mk[diff]
• vendor_libs/test_vendor_lib/Android.mk[diff]