Remove unnecessary "virtual" specifier.

These are classes that are only implementing an OsPrint method just so
that they can have a debug printing facility. They are not overriding
anything from a base class, so the "virtual" was just a bad habit.
Remove them.

src/backend/gporca/libgpopt/include/gpopt/base/CQueryContext.h

@@ -144,7 +144,7 @@ public:
 
 #ifdef GPOS_DEBUG
 	// debug print
-	virtual IOstream &OsPrint(IOstream &) const;
+	IOstream &OsPrint(IOstream &) const;
 
 	void DbgPrint() const;
 #endif	// GPOS_DEBUG

src/backend/gporca/libgpopt/include/gpopt/search/CSearchStage.h

@@ -139,7 +139,7 @@ public:
 	}
 
 	// print function
-	virtual IOstream &OsPrint(IOstream &) const;
+	IOstream &OsPrint(IOstream &) const;
 
 	// generate default search strategy
 	static CSearchStageArray *PdrgpssDefault(CMemoryPool *mp);

src/backend/gporca/libgpopt/include/gpopt/xforms/CJoinOrder.h

@@ -237,7 +237,7 @@ public:
 	virtual ~CJoinOrder();
 
 	// print function
-	virtual IOstream &OsPrint(IOstream &) const;
+	IOstream &OsPrint(IOstream &) const;
 
 	// is this a valid join combination
 	BOOL IsValidJoinCombination(SComponent *comp1, SComponent *comp2) const;

src/backend/gporca/libgpopt/include/gpopt/xforms/CJoinOrderDP.h

@@ -187,7 +187,7 @@ public:
 	}
 
 	// print function
-	IOstream &OsPrint(IOstream &) const override;
+	IOstream &OsPrint(IOstream &) const;
 
 #ifdef GPOS_DEBUG
 	void DbgPrint();

src/backend/gporca/libgpopt/include/gpopt/xforms/CJoinOrderDPv2.h

@@ -555,7 +555,7 @@ public:
 						   CBitSet **requiredBitsOnLeft = NULL);
 
 	// print function
-	IOstream &OsPrint(IOstream &) const override;
+	IOstream &OsPrint(IOstream &) const;
 
 	IOstream &OsPrintProperty(IOstream &, SExpressionProperties &) const;
 

src/backend/gporca/libgpopt/include/gpopt/xforms/CJoinOrderMinCard.h

@@ -47,7 +47,7 @@ public:
 	virtual CExpression *PexprExpand();
 
 	// print function
-	IOstream &OsPrint(IOstream &) const override;
+	IOstream &OsPrint(IOstream &) const;
 
 };	// class CJoinOrderMinCard
 

src/backend/gporca/libgpopt/src/xforms/CJoinOrder.cpp

@@ -604,6 +604,8 @@ CJoinOrder::DeriveStats(CExpression *pexpr)
 //		Helper function to print a join order class
 //
 //---------------------------------------------------------------------------
+// FIXME: the following function is completely unused even for the purpose of
+// debugging, because all subclasses implement their own OsPrint
 IOstream &
 CJoinOrder::OsPrint(IOstream &os) const
 {

src/backend/gporca/libgpos/include/gpos/memory/CMemoryPool.h

@@ -175,7 +175,7 @@ public:
 	}
 
 	// dump memory pool to given stream
-	virtual IOstream &OsPrint(IOstream &os);
+	IOstream &OsPrint(IOstream &os);
 
 	// check if a memory pool is empty
 	virtual void AssertEmpty(IOstream &os);

src/backend/gporca/libgpos/include/gpos/task/CTaskLocalStorageObject.h

@@ -55,11 +55,6 @@ public:
 	// key
 	const CTaskLocalStorage::Etlsidx m_etlsidx;
 
-#ifdef GPOS_DEBUG
-	// debug print
-	virtual IOstream &OsPrint(IOstream &os) const = 0;
-#endif	// GPOS_DEBUG
-
 };	// class CTaskLocalStorageObject
 }  // namespace gpos
 

src/backend/gporca/libgpos/server/include/unittest/gpos/task/CTaskLocalStorageTest.h

@@ -43,15 +43,6 @@ private:
 		CTestObject() : CTaskLocalStorageObject(CTaskLocalStorage::EtlsidxTest)
 		{
 		}
-
-#ifdef GPOS_DEBUG
-		// overwrite abstract member
-		IOstream &
-		OsPrint(IOstream &os) const override
-		{
-			return os;
-		}
-#endif	// GPOS_DEBUG
 	};
 
 public:

src/backend/gporca/libnaucrates/include/naucrates/statistics/CBucket.h

@@ -163,7 +163,7 @@ public:
 	BOOL IsAfter(const CBucket *bucket) const;
 
 	// print function
-	virtual IOstream &OsPrint(IOstream &os) const;
+	IOstream &OsPrint(IOstream &os) const;
 
 #ifdef GPOS_DEBUG
 	void DbgPrint() const;

src/backend/gporca/libnaucrates/include/naucrates/statistics/CHistogram.h

@@ -341,7 +341,7 @@ public:
 	}
 
 	// print function
-	virtual IOstream &OsPrint(IOstream &os) const;
+	IOstream &OsPrint(IOstream &os) const;
 
 #ifdef GPOS_DEBUG
 	void DbgPrint() const;