Add CMake support to compile WiredTiger with Icecream (icecc) on our development servers.

Context:

We have icecream distributed build support setup on our development servers. It would be worth investigating the potential build time improvements when compiling WiredTiger with our distributed icecream build farm.

This task would involves updating and testing the WiredTiger CMake build system to compile the repository with the icecream compiler. This task would most likely also involve writing a separate CMake toolchain file to source the installed icecc toolchain.