SWDEV-1 - Add EMU_ENV option

Fix FEAT-39125
Add EMU_ENV option. If it is ON, the building is for
emulation environment, thus some logics can be adjusted
to match emulation environment. If it is OFF, the
building is for regular environment.
Currently only ocltst will use the option. But it can
be used for other modules.

Change-Id: I54e1bc1309e82794b41fca2ae1f01f004138dced

opencl/tests/ocltst/module/runtime/OCLThreadTrace.cpp

@@ -28,7 +28,12 @@
 
 const static unsigned int IOThreadTrace = 3;  // number of input/oputput buffers
 static size_t SeNum = 1;                      // number of SEs
-const static unsigned int ttBufSize = 30000;  // size of thread trace buffer
+// size of thread trace buffer
+#if EMU_ENV
+const static unsigned int ttBufSize = 5000;
+#else
+const static unsigned int ttBufSize = 30000;
+#endif
 const static unsigned int InputElements = 2048;  // elements in each vector
 
 const static char* strKernel =