[ProfileData] Fix the order of tests (#95549)

Without this patch, we call getValueForSite before veryfing that we
have an expected number of value sites with getNumValueSites.

This patch fixes the order by "sinking" the call to getValueForSite.

While I am at it, this patch migrates the use of getValueForSite to
getValueArrayForSite.

Author: kazutakahirata

llvm/unittests/ProfileData/InstrProfTest.cpp

@@ -1299,9 +1299,9 @@ TEST_P(ValueProfileMergeEdgeCaseTest, value_profile_data_merge_site_trunc) {
 
   Expected<InstrProfRecord> R = Reader->getInstrProfRecord("caller", 0x1234);
   ASSERT_THAT_ERROR(R.takeError(), Succeeded());
-  std::unique_ptr<InstrProfValueData[]> VD(R->getValueForSite(ValueKind, 0));
   ASSERT_EQ(2U, R->getNumValueSites(ValueKind));
-  EXPECT_EQ(255U, R->getNumValueDataForSite(ValueKind, 0));
+  auto VD = R->getValueArrayForSite(ValueKind, 0);
+  EXPECT_THAT(VD, SizeIs(255));
   for (unsigned I = 0; I < 255; I++) {
     EXPECT_EQ(VD[I].Value, 509 - I);
     EXPECT_EQ(VD[I].Count, 1509 - I);