More updates to testing matrix

More updates to testing matrix

Covered newest cmake, while ensuring that we test the new
and old FindCUDA modules.

Added new configuration to target gcc-7.

Moved x11 responsibility to a non-GPU configuration.

Moved a simd responsbility off the tsan configuration, which has
a TODO to get moved off the GPU build slave. Updated it to gcc-7
which should be useful.

Consolidated three jobs that built on bs_nix-amd into two.

Fixed minor issues with possible sprintf over-run or snprintf
truncation, and possible use of uninitialized pointers.

Fixed release matrix use of gcc-[567] versions. The release-2016
branch usess older compiler versions.

Change-Id: Iafd6a440fd763ef6c645bb094579e0ec6875621b