Reland "[factory] Make NewByteArray return canonical empty byte array"

This is a reland of 8d3c8093 to make
UBsan happy: memcopy (and therefore MemCopy) seems to expect a non-null
src even when the given size is 0, so avoid calling it in that case.

Original change's description:
> [factory] Make NewByteArray return canonical empty byte array
>
> ... for length = 0, analogously to what e.g. NewFixedArray does.
>
> Simplify some call sites that had special handling for this case
> (there are others that didn't).
>
> Change-Id: Ib3de5506300e967aca072fad53df7ab04ef68839
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3009225
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#75629}

Change-Id: Ib8dc471d63a4b11b846e9d436555a3615902b66f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3014456Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75642}

src/compiler/backend/code-generator.cc

@@ -983,10 +983,6 @@ Handle<PodArray<InliningPosition>> CreateInliningPositions(
     OptimizedCompilationInfo* info, Isolate* isolate) {
   const OptimizedCompilationInfo::InlinedFunctionList& inlined_functions =
       info->inlined_functions();
-  if (inlined_functions.size() == 0) {
-    return Handle<PodArray<InliningPosition>>::cast(
-        isolate->factory()->empty_byte_array());
-  }
   Handle<PodArray<InliningPosition>> inl_positions =
       PodArray<InliningPosition>::New(
           isolate, static_cast<int>(inlined_functions.size()),

src/heap/factory-base.cc

@@ -170,6 +170,7 @@ Handle<ByteArray> FactoryBase<Impl>::NewByteArray(int length,
     FATAL("Fatal JavaScript invalid size error %d", length);
     UNREACHABLE();
   }
+  if (length == 0) return impl()->empty_byte_array();
   int size = ByteArray::SizeFor(length);
   HeapObject result = AllocateRawWithImmortalMap(
       size, allocation, read_only_roots().byte_array_map());

src/heap/factory-base.h

@@ -115,15 +115,17 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) FactoryBase
       int length, AllocationType allocation = AllocationType::kYoung);
 
   // Allocates a weak fixed array-like object with given map and initialized
-  // with undefined values.
+  // with undefined values. Length must be > 0.
   Handle<WeakFixedArray> NewWeakFixedArrayWithMap(
       Map map, int length, AllocationType allocation = AllocationType::kYoung);
 
   // Allocates a fixed array which may contain in-place weak references. The
   // array is initialized with undefined values
+  // The function returns a pre-allocated empty weak fixed array for length = 0.
   Handle<WeakFixedArray> NewWeakFixedArray(
       int length, AllocationType allocation = AllocationType::kYoung);
 
+  // The function returns a pre-allocated empty byte array for length = 0.
   Handle<ByteArray> NewByteArray(
       int length, AllocationType allocation = AllocationType::kYoung);