ansible: add cmake for AIX

[richardlau]

Install cmake on AIX from the AIX Toolbox for Linux Applications.

Refs: #2097
Refs: libuv/libuv#2731

cc @AshCripps @sam-github

[richardlau]

I've rerun ansible on test-ibm-aix71-ppc64_be-1 and test-ibm-aix71-ppc64_be-2. cmake is installed in /opt/freeware/bin:

bash-5.0$ /opt/freeware/bin/cmake --version
cmake version 3.14.3

CMake suite maintained and supported by Kitware (kitware.com/cmake).
bash-5.0$

[mhdawson]

If that works, then works for me.

[mhdawson]

LGTM

[richardlau]

/opt/freeware/bin isn't currently on the PATH for AIX. I'll add it as part of select-compiler.sh so we don't have to do it in every job that needs cmake.