Remove broken %_Log functionality.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 5b5b7ea52c17404350b7e09f04a743d5eb47a67c..4ffae76391a0430b49b1eedd7ce5da2ca9ebd4ac 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -2447,14 +2447,6 @@ bool MacroAssembler::AllowThisStubCall(CodeStub* stub) {
 }
 
 
-void MacroAssembler::IllegalOperation(int num_arguments) {
-  if (num_arguments > 0) {
-    add(sp, sp, Operand(num_arguments * kPointerSize));
-  }
-  LoadRoot(r0, Heap::kUndefinedValueRootIndex);
-}
-
-
 void MacroAssembler::IndexFromHash(Register hash, Register index) {
   // If the hash field contains an array index pick it out. The assert checks
   // that the constants for the maximum number of digits for an array index
@@ -2650,10 +2642,7 @@ void MacroAssembler::CallRuntime(const Runtime::Function* f,
   // If the expected number of arguments of the runtime function is
   // constant, we check that the actual number of arguments match the
   // expectation.
-  if (f->nargs >= 0 && f->nargs != num_arguments) {
-    IllegalOperation(num_arguments);
-    return;
-  }
+  CHECK(f->nargs < 0 || f->nargs == num_arguments);
 
   // TODO(1236192): Most runtime routines don't need the number of
   // arguments passed in because it is constant. At some point we