[memprof] Simplify IndexedMemProfRecord::operator== (NFC) (#88986)

llvm::SmallVector::operator== exactly meets our needs.

Author: kazutakahirata

llvm/include/llvm/ProfileData/MemProf.h

@@ -370,14 +370,9 @@ struct IndexedMemProfRecord {
   size_t serializedSize(IndexedVersion Version) const;
 
   bool operator==(const IndexedMemProfRecord &Other) const {
-    if (Other.AllocSites.size() != AllocSites.size())
+    if (Other.AllocSites != AllocSites)
       return false;
 
-    for (size_t I = 0; I < AllocSites.size(); I++) {
-      if (AllocSites[I] != Other.AllocSites[I])
-        return false;
-    }
-
     if (Other.CallSiteIds != CallSiteIds)
       return false;
     return true;