Serial flasher Tests

##Overview

Two kinds of tests are written for serial flasher:

Host tests
Qemu tests

Qemu tests uses emulated esp32 to test correctness of the library.

Installation (Only for qemu tests)

Please refer to building qemu for instructions how to compile.

Build and run

Qemu test

QEMU_PATH environment variable pointing to compiled qemu/build/xtensa-softmmu/qemu-system-xtensa has to be defined.

export QEMU_PATH=path_to_qemu-system-xtensa
./run_test.sh qemu

Host test

./run_test.sh host