fix: remove some unnecessary V8_EXPORT_PRIVATE annotations

When building in debug mode for Windows on Arm, Clang reports the
following error without this patch:

  error: attribute 'dllexport' cannot be applied to member of
  'dllexport' class.

Change-Id: Ib3b12fce7daa368f9464b080ac7a7bce1ddd5370
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1611799Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Richard Townsend <richard.townsend@arm.com>
Cr-Commit-Position: refs/heads/master@{#61493}

src/arm64/decoder-arm64.h

@@ -120,7 +120,7 @@ class V8_EXPORT_PRIVATE DispatchingDecoderVisitor : public DecoderVisitor {
   //
   // will call in order visitor methods in V3, V2, V1, V4.
   void AppendVisitor(DecoderVisitor* visitor);
-  V8_EXPORT_PRIVATE void PrependVisitor(DecoderVisitor* visitor);
+  void PrependVisitor(DecoderVisitor* visitor);
   void InsertVisitorBefore(DecoderVisitor* new_visitor,
                            DecoderVisitor* registered_visitor);
   void InsertVisitorAfter(DecoderVisitor* new_visitor,

src/arm64/macro-assembler-arm64.h

@@ -2093,7 +2093,7 @@ class V8_EXPORT_PRIVATE UseScratchRegisterScope {
     DCHECK_EQ(availablefp_->type(), CPURegister::kVRegister);
   }
 
-  V8_EXPORT_PRIVATE ~UseScratchRegisterScope();
+  ~UseScratchRegisterScope();
 
   // Take a register from the appropriate temps list. It will be returned
   // automatically when the scope ends.
@@ -2110,7 +2110,7 @@ class V8_EXPORT_PRIVATE UseScratchRegisterScope {
   VRegister AcquireSameSizeAs(const VRegister& reg);
 
  private:
-  V8_EXPORT_PRIVATE static CPURegister AcquireNextAvailable(
+  static CPURegister AcquireNextAvailable(
       CPURegList* available);
 
   // Available scratch registers.