arm: add host uart driver tests

All host tests currently pass
Some async refactors may not work well on device, will try later

arm/dev.dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu
+
+RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
+    apt-get install -y make clang libgmock-dev gdb && \
+    apt-get clean && rm -rf /var/lib/apt/lists