Query hostname for test executables at runtime

[JohnJacobsonIII]

Feature Request

Description: Currently, system metadata such as host name, compilation settings, and filenames are set for each executable at compile time. As we consider applying distributed workflow tools to FLiT testing, logging for program analysis and performance modeling will require accurate data on the runtime environment.

Suggested change: Query the host name at runtime for each executable. It may be necessary to add separate metadata for test run host and test comparison host as these steps could be run on separate nodes in theory; otherwise, collecting host during test runs should be sufficient.

Currently all tests are run by one call to the executable so no need for more granularity than executable file level, I believe.