tests: Use %abs_tmp instead of ./%t to make these tests portable to 'lit'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81663 91177308-0d34-0410-b5e6-96231b3b80d8

test/LLVMC/C++/hello.cpp

@@ -1,6 +1,6 @@
 // Test that we can compile C++ code.
 // RUN: llvmc %s -o %t
-// RUN: ./%t | grep hello
+// RUN: %abs_tmp | grep hello
 #include <iostream>
 
 int main() {