inputflinger fuzzers: remove FuzzContainer.getPolicyConfig

Because FuzzInputReaderPolicy::getReaderConfiguration does nothing, any
calls to getPolicyConfig can be replaced with default
InputReaderConfiguration structs. This makes it clearer where where a
fuzzer is getting its configuration from, and therefore makes it easier
to understand the fuzzer without having to dig into FuzzContainer and
FuzzInputReaderPolicy.

InputReaderPolicyInterface::getReaderConfiguration is not called by any
of the code being fuzzed, so it's unlikely that
FuzzInputReaderPolicy::getReaderConfiguration will need to be modified
to return a non-default InputReaderConfiguration in future.

Bug: 245989146
Test: build and briefly run all modified fuzzers
      $ SANITIZE_TARGET=hwaddress make ${FUZZER_NAME}
      $ cd $ANDROID_PRODUCT_OUT
      $ adb root
      $ adb sync data
      $ adb shell /data/fuzz/$(get_build_var TARGET_ARCH)/${FUZZER_NAME}/${FUZZER_NAME}
Change-Id: If933e1ce81439831b24c61dde1c2d24ed1a00942