[CFLAA] Be more aggressive with interprocedural analysis.

This patch makes us perform interprocedural analysis on functions that
don't have internal linkage. It also removes a test that should've been
deleted in an earlier commit (since other tests now cover everything
that the newly-removed test covers).

Patch by Jia Chen.

Differential Revision: http://reviews.llvm.org/D21513

llvm-svn: 273229
diff --git a/llvm/lib/Analysis/CFLAliasAnalysis.cpp b/llvm/lib/Analysis/CFLAliasAnalysis.cpp
index bebc614..8f3c497 100644
--- a/llvm/lib/Analysis/CFLAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/CFLAliasAnalysis.cpp
@@ -377,7 +377,7 @@
   }
 
   static bool isFunctionExternal(Function *Fn) {
-    return Fn->isDeclaration() || !Fn->hasLocalLinkage();
+    return !Fn->hasExactDefinition();
   }
 
   bool tryInterproceduralAnalysis(CallSite CS,