[stubs] Split ToNumberStub into reusable subparts.

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index 33b4172766c1a02efbec32a0b3dd84c0adf3734a..f32630444e32aca934dea7654c71e6467974e333 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -1306,6 +1306,9 @@ class MacroAssembler: public Assembler {
   // Jump if either of the registers contain a smi.
   void JumpIfEitherSmi(Register reg1, Register reg2, Label* on_either_smi);
 
+  // Abort execution if argument is a number, enabled via --debug-code.
+  void AssertNotNumber(Register object);
+
   // Abort execution if argument is a smi, enabled via --debug-code.
   void AssertNotSmi(Register object);
   void AssertSmi(Register object);