Wrap all references to build artifacts in the LLDB testsuite (NFC)

in TestBase::getBuildArtifact(). This NFC commit is in preparation for
https://reviews.llvm.org/D42281 (compile the LLDB tests out-of-tree).

Differential Revision: https://reviews.llvm.org/D42280

llvm-svn: 323007
diff --git a/lldb/packages/Python/lldbsuite/test/lldbinline.py b/lldb/packages/Python/lldbsuite/test/lldbinline.py
index 70a0dda..3f10b2a 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbinline.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbinline.py
@@ -166,8 +166,7 @@
         exec(__command, globals(), locals())
 
     def do_test(self):
-        exe_name = "a.out"
-        exe = os.path.join(os.getcwd(), exe_name)
+        exe = self.getBuildArtifact("a.out")
         source_files = [f for f in os.listdir(os.getcwd()) if source_type(f)]
         target = self.dbg.CreateTarget(exe)