SWDEV-1 - Rearrange error conditions in elapsed time

- when the first argument is null API should return hipErrorInvalidValue
- but when first and second argument both are null API was returning hipErrorInvalidHandle causing catch2 event tests to fail

Change-Id: I0978ce8b8462e4baa043be75a40b5bc45b036bb6

hipamd/src/hip_event.cpp

@@ -259,14 +259,14 @@ hipError_t hipEventDestroy(hipEvent_t event) {
 hipError_t hipEventElapsedTime(float *ms, hipEvent_t start, hipEvent_t stop) {
   HIP_INIT_API(hipEventElapsedTime, ms, start, stop);
 
-  if (start == nullptr || stop == nullptr) {
-    HIP_RETURN(hipErrorInvalidHandle);
-  }
-
   if (ms == nullptr) {
     HIP_RETURN(hipErrorInvalidValue);
   }
 
+  if (start == nullptr || stop == nullptr) {
+    HIP_RETURN(hipErrorInvalidHandle);
+  }
+
   hip::Event* eStart = reinterpret_cast<hip::Event*>(start);
   hip::Event* eStop  = reinterpret_cast<hip::Event*>(stop);