Fix DoesValueTypeContainGCRefs in the interpreter (#121846)

There was a mistake in the implementation that prevented it from working
correctly in some cases. The return value of the getClassSize() is not a
number of slots filled in the array, but a number of GC references in
the array. So if there were e.g. three slots and there was one GC
reference in the second slot, the DoesValueTypeContainGCRefs returned
false.

Author: janvorli

src/coreclr/interpreter/compiler.cpp

@@ -2886,17 +2886,9 @@ static bool DoesValueTypeContainGCRefs(COMP_HANDLE compHnd, CORINFO_CLASS_HANDLE
     // getClassGClayout assumes it's given a buffer of exactly this size
     unsigned maxGcPtrs = (size + sizeof(void *) - 1) / sizeof(void *);
     BYTE *gcLayout = (BYTE *)alloca(maxGcPtrs + 1);
-    uint32_t numSlots = compHnd->getClassGClayout(clsHnd, gcLayout);
+    uint32_t numGCRefs = compHnd->getClassGClayout(clsHnd, gcLayout);
 
-    for (uint32_t i = 0; i < numSlots; ++i)
-    {
-        if (gcLayout[i] != TYPE_GC_NONE)
-        {
-            return true;
-        }
-    }
-
-    return false;
+    return numGCRefs > 0;
 }
 
 void InterpCompiler::ConvertFloatingPointStackEntryToStackType(StackInfo* entry, StackType type)