[stubs] Split ToNumberStub into reusable subparts.

src/arm64/macro-assembler-arm64.cc

Index: src/arm64/macro-assembler-arm64.cc
diff --git a/src/arm64/macro-assembler-arm64.cc b/src/arm64/macro-assembler-arm64.cc
index 530182cdb7ce8707f0a28aec70de1a6dd9be19b5..0a605b52d3cb0d145b61a461a8b46f7d8e2ae215 100644
--- a/src/arm64/macro-assembler-arm64.cc
+++ b/src/arm64/macro-assembler-arm64.cc
@@ -1690,6 +1690,18 @@ void MacroAssembler::AssertPositiveOrZero(Register value) {
   }
 }
 
+void MacroAssembler::AssertNotNumber(Register value) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    Tst(value, kSmiTagMask);
+    Check(ne, kOperandIsANumber);
+    Label done;
+    JumpIfNotHeapNumber(value, &done);
+    Abort(kOperandIsANumber);
+    Bind(&done);
+  }
+}
+
 void MacroAssembler::AssertNumber(Register value) {
   if (emit_debug_code()) {
     Label done;