Remove Circle CI script

We are running an equivalent set of test by other means and therefore
this script is no longer needed.

circle.yml

@@ -1,44 +0,0 @@
-# Purpose:
-# - To test and prove that a new commit in  the mbed TLS repository builds
-# and integrates with mbed-os properly.
-#           AND
-# - To test and prove that the current development head of mbed TLS builds
-# and integrates with the current mbed-os master branch.
-#
-# The script fetches all the prerequisites and builds the mbed TLS 'tls-client'
-# example. This script is triggered by every commit and once each night and the
-# exact behaviour depends on how it was triggered:
-# - If it is a nightly build then it builds the mbed TLS development head with
-#   mbed-os master.
-# - If it was triggered by the commit, then it builds the example with mbed TLS
-#   at that commit and mbed-os at the commit pointed by mbed-os.lib in the
-#   example repository.
-
-test:
-    override:
-        - cd ../mbed-os-example-tls/tls-client/ && mbed compile -m K64F -t GCC_ARM -c
-
-dependencies:
-    pre:
-        # Install gcc-arm
-        - cd .. && wget "https://launchpad.net/gcc-arm-embedded/4.9/4.9-2015-q3-update/+download/gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2"
-        - cd .. && tar -xvjf gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2
-        - ln -s ../gcc-arm-none-eabi-4_9-2015q3/bin/* ../bin/
-        # Install mbed-cli
-        - cd ../ && git clone https://github.com/ARMmbed/mbed-cli.git
-        - cd ../mbed-cli && sudo -H pip install -e .
-        # Get the sample application
-        - cd ../ && git clone git@github.com:ARMmbed/mbed-os-example-tls.git
-        # Get mbed-os
-        - cd ../mbed-os-example-tls/tls-client && mbed deploy
-        # Update mbed-os to master only if it is a nightly build
-        - >
-            if [ -n "${RUN_NIGHTLY_BUILD}" ]; then
-                cd ../mbed-os-example-tls/tls-client/mbed-os/ && mbed update master;
-            fi
-        # Import mbedtls current revision
-        - ln -s ../../../../../../../mbedtls/ ../mbed-os-example-tls/tls-client/mbed-os/features/mbedtls/importer/TARGET_IGNORE/mbedtls
-        - cd ../mbed-os-example-tls/tls-client/mbed-os/features/mbedtls/importer/ && make
-    override:
-        # Install the missing python packages
-        - cd ../mbed-os-example-tls/tls-client/mbed-os/ && sudo -H pip install -r requirements.txt