Android: Introduce ANDROID_HOST_BUILD and rework logging.

Android: Introduce ANDROID_HOST_BUILD and rework logging.

Avoid using the Android logger directly. Instead, use the Common/Debug
and OpenGL/common/debug paths instead, which abstracts away use of the
logger.

Add ANDRIOD_HOST_BUILD to tell the build we are building an Android
swiftshader, but minimizing the use of platform features such as the
logger.

Change-Id: Ic6c70843d947c568d0e29fe66c55af74b8559a59
Reviewed-on: https://swiftshader-review.googlesource.com/18028
Tested-by: Alistair Strachan <astrachan@google.com>
Reviewed-by: Greg Hartman <ghartman@google.com>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>