[stubs] Split ToNumberStub into reusable subparts.

src/arm64/macro-assembler-arm64.h

Index: src/arm64/macro-assembler-arm64.h
diff --git a/src/arm64/macro-assembler-arm64.h b/src/arm64/macro-assembler-arm64.h
index b9414b4e75db8b8cb481b14666a39e1fcc70d6a9..bb04adcceb665eeaf04d71687ade45a6c5e653cb 100644
--- a/src/arm64/macro-assembler-arm64.h
+++ b/src/arm64/macro-assembler-arm64.h
@@ -987,6 +987,7 @@ class MacroAssembler : public Assembler {
 
   // Abort execution if argument is not a number (heap number or smi).
   void AssertNumber(Register value);
+  void AssertNotNumber(Register value);
 
   void JumpIfHeapNumber(Register object, Label* on_heap_number,
                         SmiCheckType smi_check_type = DONT_DO_SMI_CHECK);