Move a method from IdentifierTable.h out of line and remove the SmallString include.

Fix all the transitive include users.

llvm-svn: 149783
diff --git a/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
index 2e1863c..d77d4d6 100644
--- a/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
@@ -57,6 +57,7 @@
 #include "clang/AST/Stmt.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/Support/ErrorHandling.h"