SWDEV-505853 - Fix Unit_hipMemPoolApi_BasicAlloc in mgpu

Unit_hipMemPoolApi_BasicAlloc expects to work on device 0, but other
tests will set not-0 devices in mgpu. This leads to hang of
Unit_hipMemPoolApi_BasicAlloc. Fix by set device 0 in head code
of Unit_hipMemPoolApi_BasicAlloc.

SWDEV-508872 - Fix Perf_hipPerfMemFill_test

When mem size is 2G, the test is so slow that it looks like stuckness.
Set top mem size to 1G can make the test pass in an acceptiable time.

Change-Id: Ie26dbf597e5ba8cb898d1aae5ed5ecf0267c3228

catch/perftests/memory/hipPerfMemFill.cc

@@ -84,7 +84,7 @@ template<class T>
 class hipPerfMemFill {
  private:
   static constexpr int NUM_START = 27;
-  static constexpr int NUM_SIZE = 5;
+  static constexpr int NUM_SIZE = 4;
   static constexpr int NUM_ITER = 10;
   static constexpr double NUM_1GB = 1024.0 * 1024.0 * 1024.0;
   size_t totalSizes_[NUM_SIZE];
@@ -96,7 +96,7 @@ class hipPerfMemFill {
  public:
   hipPerfMemFill() {
     for (int i = 0; i < NUM_SIZE; i++) {
-       // 128M, 256M, 512M, 1024M, 2048M
+       // 128M, 256M, 512M, 1024M
       totalSizes_[i] = 1ull << (i + NUM_START);
     }
   }