cppgc: Fix iOS arm64 compile

Use same mangling as for x64 MacOS.

Bug: v8:10517
Change-Id: I26d7c4ab950d86e9010e76a0a6d71ea266639d02
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2192653Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67701}

src/heap/cppgc/asm/arm64/push_registers_asm.cc

@@ -16,12 +16,19 @@
 // Calling convention source:
 // https://en.wikipedia.org/wiki/Calling_convention#ARM_(A64)
 
-asm(".globl PushAllRegistersAndIterateStack             \n"
-#ifndef _WIN64
+asm(
+#if defined(__APPLE__)
+    ".globl _PushAllRegistersAndIterateStack            \n"
+    ".private_extern _PushAllRegistersAndIterateStack   \n"
+    "_PushAllRegistersAndIterateStack:                  \n"
+#else  // !defined(__APPLE__)
+    ".globl PushAllRegistersAndIterateStack             \n"
+#if !defined(_WIN64)
     ".type PushAllRegistersAndIterateStack, %function   \n"
     ".hidden PushAllRegistersAndIterateStack            \n"
-#endif
+#endif  // !defined(_WIN64)
     "PushAllRegistersAndIterateStack:                   \n"
+#endif  // !defined(__APPLE__)
     // x19-x29 are callee-saved.
     "  stp x19, x20, [sp, #-16]!                        \n"
     "  stp x21, x22, [sp, #-16]!                        \n"