Module test correction and hipModuleUnload API

- Corrected the hipModule.cpp test to minimal code
- Added hipModuleUnload API
- Added hipModuleUnload API test

Change-Id: I9c40337043d7972a570b795e1bfc104bd2c4d8aa

include/hcc_detail/hip_runtime_api.h

@@ -1113,6 +1113,8 @@ hipError_t hipDriverGetVersion(int *driverVersion) ;
 
 hipError_t hipModuleLoad(hipModule *module, const char *fname);
 
+hipError_t hipModuleUnload(hipModule module);
+
 hipError_t hipModuleGetFunction(hipFunction *function, hipModule module, const char *kname);
 
 hipError_t hipLaunchModuleKernel(hipFunction f,