Bug 1673053 - Remove unnecessary #ifdef, now that we no longer have 32 bit macOS builds. r=haik

Differential Revision: https://phabricator.services.mozilla.com/D94617

widget/cocoa/VibrancyManager.mm

@@ -168,12 +168,7 @@ enum { NSVisualEffectMaterialSelection = 4 };
 }
 
 static bool ComputeSystemSupportsVibrancy() {
-#ifdef __x86_64__
   return NSClassFromString(@"NSAppearance") && NSClassFromString(@"NSVisualEffectView");
-#else
-  // objc_allocateClassPair doesn't work in 32 bit mode, so turn off vibrancy.
-  return false;
-#endif
 }
 
 /* static */ bool VibrancyManager::SystemSupportsVibrancy() {