[ARC,test] Change llc -march= to -mtriple=

Similar to 806761a

-mtriple= specifies the full target triple while -march= merely sets the
architecture part of the default target triple (e.g. Windows, macOS),
leaving a target triple which may not make sense.

Therefore, -march= is error-prone and not recommended for tests without
a target triple. The issue has been benign as we recognize
arc-apple-darwin as ELF instead of rejecting it outrightly.

Author: MaskRay

llvm/test/CodeGen/ARC/addrmode.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 ; CHECK-LABEL: copy
 ; CHECK-NOT: add

llvm/test/CodeGen/ARC/alu.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 ; CHECK-LABEL: add_r
 ; CHECK: add %r0, %r{{[01]}}, %r{{[01]}}

llvm/test/CodeGen/ARC/brcc.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 ; CHECK-LABEL: brcc1:
 ; CHECK:         brne %r0, %r1, @.LBB0_2

llvm/test/CodeGen/ARC/call.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 
 declare i32 @goo1(i32) nounwind

llvm/test/CodeGen/ARC/intrinsics.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 target triple = "arc"
 

llvm/test/CodeGen/ARC/ldst.ll

@@ -1,4 +1,4 @@
-; RUN: llc -march=arc < %s | FileCheck %s
+; RUN: llc -mtriple=arc < %s | FileCheck %s
 
 ; CHECK-LABEL: load32
 ; CHECK: ld %r0, [%r0,16000]