Try to fix test from r293004

This test broke on a lot of non-x86 buildbots with "unknowm CPU" errors. I don't
see anything platform-specific about this test, and it seems to work fine on ARM
if we just remove the -triple i686 flags from the run line.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293026 91177308-0d34-0410-b5e6-96231b3b80d8

test/Frontend/preprocessed-input.c

 // RUN: %clang -E -o %t.i %s
-// RUN: %clang -Xclang -triple -Xclang i686-linux-gnu -c -o %t.o %t.i
+// RUN: %clang -c -o %t.o %t.i
 // RUN: llvm-objdump -t %t.o | FileCheck %s
 // CHECK: l{{ +}}df{{ +}}*ABS*{{ +}}{{0+}}{{.+}}preprocessed-input.c{{$}}