[fastcall] Enhance FastApiTypedArray with aligned data getter

This CL adds a getStorageIfAligned method to obtaining a typed pointer
to the underlying TypedArray data, if the pointer to it is properly
aligned.

Bug: chromium:1052746
Change-Id: Ie8cb3438135b0da060e2b42ec71bba0e72ae4f5e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3195875Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77184}

include/v8-fast-api-calls.h

@@ -335,6 +335,14 @@ struct FastApiTypedArray : public FastApiTypedArrayBase {
     return tmp;
   }
 
+  bool getStorageIfAligned(T** elements) const {
+    if (reinterpret_cast<uintptr_t>(data_) % alignof(T) != 0) {
+      return false;
+    }
+    *elements = reinterpret_cast<T*>(data_);
+    return true;
+  }
+
  private:
   // This pointer should include the typed array offset applied.
   // It's not guaranteed that it's aligned to sizeof(T), it's only