[Arm64] Remove buggy --optimize-for-size branch in PushMultipleTimes.

The helper would cause the stack to be unaligned during pushes which caused issues
on Arm64. PushMultipleTimes is only used once by InterpreterEntryTrampoline,
therefore it doesn't make sense to change it's behaviour for --optimize-for-size.

Change-Id: I3bc7d39bc38ffd22a3ee6cca1cdafe5d656d77b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1773275
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63443}

src/codegen/arm64/macro-assembler-arm64.cc

@@ -1139,20 +1139,6 @@ void MacroAssembler::PushMultipleTimes(CPURegister src, Register count) {
   UseScratchRegisterScope temps(this);
   Register temp = temps.AcquireSameSizeAs(count);
 
-  if (FLAG_optimize_for_size) {
-    Label loop, done;
-
-    Subs(temp, count, 1);
-    B(mi, &done);
-
-    // Push all registers individually, to save code size.
-    Bind(&loop);
-    Subs(temp, temp, 1);
-    PushHelper(1, src.SizeInBytes(), src, NoReg, NoReg, NoReg);
-    B(pl, &loop);
-
-    Bind(&done);
-  } else {
   Label loop, leftover2, leftover1, done;
 
   Subs(temp, count, 4);
@@ -1175,7 +1161,6 @@ void MacroAssembler::PushMultipleTimes(CPURegister src, Register count) {
   PushHelper(1, src.SizeInBytes(), src, NoReg, NoReg, NoReg);
 
   Bind(&done);
-  }
 }
 
 void TurboAssembler::PushHelper(int count, int size, const CPURegister& src0,