Revert r194865 and r194874.

This change is incorrect. If you delete virtual destructor of both a base class
and a subclass, then the following code:
  Base *foo = new Child();
  delete foo;
will not cause the destructor for members of Child class. As a result, I observe
plently of memory leaks. Notable examples I investigated are:
ObjectBuffer and ObjectBufferStream, AttributeImpl and StringSAttributeImpl.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194997 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/ExecutionEngine/MCJIT/MCJITMultipleModuleTest.cpp

@@ -18,13 +18,7 @@
 
 using namespace llvm;
 
-class MCJITMultipleModuleTest : public testing::Test,
-                                public MCJITTestBase {
-public:
-  virtual ~MCJITMultipleModuleTest();
-};
-
-MCJITMultipleModuleTest::~MCJITMultipleModuleTest() {}
+class MCJITMultipleModuleTest : public testing::Test, public MCJITTestBase {};
 
 namespace {