Use an i686 triple for this test now that it uses stdcall

There seems to be a crash here if we have a calling convention attribute
that gets ignored and then we instantiate templates.

llvm-svn: 186719

clang/test/SemaTemplate/instantiate-function-params.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -verify %s
 
 // PR6619
 template<bool C> struct if_c { };
@@ -86,6 +86,8 @@ namespace InstantiateFunctionTypedef {
     typedef int stdfunctype(int, int) __attribute__((stdcall));
     __attribute__((stdcall)) functype stdfunc1;
     stdfunctype stdfunc2;
+
+    // FIXME: Test a calling convention not supported by this target.
   };
 
   void f(X<int> x) {