[PATCH] [lsan] Enable i386 support. Also rework the lit test configs.

[Kostya Serebryany]

  LGTM for C++ part with one nit.
  Please wait for glider/samsonov's review for the non-C++ part.


================
Comment at: lib/lsan/lsan_interceptors.cc:15
@@ -14,1 +14,3 @@
 
+#include <stddef.h>
+
----------------
don't include stddef here, instead move operator new/delete into a separate file and include stddef there


http://llvm-reviews.chandlerc.com/D1015