Adjust test to only compile and not link

Compilation is all that's needed here - linking helped avoid certain
false positives in llvm-dwarfdump --verify related to overlapping
functions when those functions were actually in distinct sections.
That's since been fixed, so we can adjust the test to only compile, and
not link.

cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names.cpp

@@ -1,7 +1,5 @@
-// RUN: rm -rf %t
-// RUN: mkdir %t
-// RUN: %clang -fblocks %s -o %t/a.out -g -Xclang -gsimple-template-names=mangled -Xclang -debug-forward-template-params 
-// RUN: llvm-dwarfdump %t/a.out --verify
+// RUN: %clang %s -c -o - -g -Xclang -gsimple-template-names=mangled -Xclang -debug-forward-template-params \
+// RUN:   | llvm-dwarfdump --verify -
 // REQUIRES: native
 template<typename ...Ts>
 struct t1 {