Revert "[VM] Move kernel buffer created by IKG into external typed data with finalizer"

This reverts commit 78462ecbdd.

Reason for revert: There is code which doesn't hang on to the ExternalTypedData and therefore causes use-after-free.

Original change's description:
> [VM] Move kernel buffer created by IKG into external typed data with finalizer
> 
> This fixes a memory leak which shows up by lsan in certain situations.
> 
> Change-Id: Ib0d18520a2e57562bc72e79c8e4f070c16509268
> Reviewed-on: https://dart-review.googlesource.com/66383
> Reviewed-by: Ryan Macnak <rmacnak@google.com>

TBR=kustermann@google.com,rmacnak@google.com,zra@google.com

Change-Id: I71981b17264b50592b60d844fb3ca795371faaa6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/66580
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>

runtime/vm/isolate_reload.cc

@@ -614,22 +614,8 @@ void IsolateReloadContext::Reload(bool force_reload,
         return;
       }
       did_kernel_compilation = true;
-
-      // The ownership of the kernel buffer goes now to the VM.
-      const ExternalTypedData& typed_data = ExternalTypedData::Handle(
-          Z,
-          ExternalTypedData::New(kExternalTypedDataUint8ArrayCid, retval.kernel,
-                                 retval.kernel_size, Heap::kOld));
-      struct Helper {
-        static void Finalize(void* isolate_callback_data,
-                             Dart_WeakPersistentHandle handle,
-                             void* data) {
-          free(data);
-        }
-      };
-      typed_data.AddFinalizer(retval.kernel, Helper::Finalize,
-                              retval.kernel_size);
-      kernel_program.set(kernel::Program::ReadFromTypedData(typed_data));
+      kernel_program.set(
+          kernel::Program::ReadFromBuffer(retval.kernel, retval.kernel_size));
     }
 
     kernel::KernelLoader::FindModifiedLibraries(kernel_program.get(), I,

runtime/vm/kernel.h

@@ -66,8 +66,6 @@ class Program {
   static Program* ReadFromBuffer(const uint8_t* buffer,
                                  intptr_t buffer_length,
                                  const char** error = nullptr);
-  static Program* ReadFromTypedData(const ExternalTypedData& typed_data,
-                                    const char** error = nullptr);
 
   bool is_single_program() { return single_program_; }
   NameIndex main_method() { return main_method_reference_; }

runtime/vm/kernel_binary.cc

@@ -161,12 +161,6 @@ Program* Program::ReadFromBuffer(const uint8_t* buffer,
   return kernel::Program::ReadFrom(&reader, error);
 }
 
-Program* Program::ReadFromTypedData(const ExternalTypedData& typed_data,
-                                    const char** error) {
-  kernel::Reader reader(typed_data);
-  return kernel::Program::ReadFrom(&reader, error);
-}
-
 }  // namespace kernel
 }  // namespace dart
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)