Adding timeout functionality/EnvVar to TestBed (#1044)

* Adding timeout functionality/EnvVar to TestBed
* updating timeout unit to microseconds

Signed-off-by: Tim Hu <timhu102@amd.com>

[ROCm/rccl commit: 9c0ef11ac7]

projects/rccl/test/ReduceTests.cpp

@@ -7,7 +7,7 @@
 
 namespace RcclUnitTesting
 {
-    TEST(Reduce, OutOfPlace)
+  TEST(Reduce, OutOfPlace)
   {
     TestBed testBed;