* The global variable `gTestFastRelaxed` has state which is used to
control the behaviour of the compiler flag `-cl-fast-relaxed-math` and
the precision testing of relaxed, fp32 and fp64 types. This is confusing
since the global variable is being set and read in different translation
units, making it very difficult to reason about the logic of the brute
force framework. It is particular difficult to follow since the global
variables is cached and then turned off in the case of fp32 and f64 in
order to use the same code path as relaxed testing, after it is then
turned back on.
* Remove uses of the global variable outside of `main.cpp` (the global
variable remains in use within `main.cpp` since it is a command line
option and used to turn of relaxed testing completely). Replace all uses
of the global variable with boolean `relaxedMode` which is passed as a
function paramter but replaces `gTestFastRelaxed` semantically.
