Added fast math flag

1. Use -DHIP_FAST_MATH to make precise math functions compiled to fast math
2. Added double fast math functions for sqrt
3. Changed hipcc to parse -use_fast_math (not working)
4. Added passed tag to hipFloatMath test

Change-Id: I72884b2436b4efe61e9a9297346c1358fee38a2d

tests/src/deviceLib/hipFloatMath.cpp

@@ -58,4 +58,5 @@ int main(){
   hipMalloc((void**)&Ind, SIZE);
   hipMalloc((void**)&Outd, SIZE);
   hipLaunchKernel(floatMath, dim3(LEN,1,1), dim3(1,1,1), 0, 0, Ind, Outd);
+  passed();
 }