Remove -Wno-unused-parameter and -Wno-sign-promo from base cflags.

Fix associated errors about unused paramenters and implict sign conversions.
For sign conversion this was largely in the area of enums, so add ostream
operators for the effected enums and fix tools/generate-operator-out.py.
Tidy arena allocation code and arena allocated data types, rather than fixing
new and delete operators.
Remove dead code.

Change-Id: I5b433e722d2f75baacfacae4d32aef4a828bfe1b
diff --git a/compiler/utils/arena_bit_vector.cc b/compiler/utils/arena_bit_vector.cc
index de35f3d..f17e5a9 100644
--- a/compiler/utils/arena_bit_vector.cc
+++ b/compiler/utils/arena_bit_vector.cc
@@ -16,12 +16,12 @@
 
 #include "arena_allocator.h"
 #include "arena_bit_vector.h"
-#include "base/allocator.h"
 
 namespace art {
 
 template <typename ArenaAlloc>
-class ArenaBitVectorAllocator FINAL : public Allocator {
+class ArenaBitVectorAllocator FINAL : public Allocator,
+    public ArenaObject<kArenaAllocGrowableBitMap> {
  public:
   explicit ArenaBitVectorAllocator(ArenaAlloc* arena) : arena_(arena) {}
   ~ArenaBitVectorAllocator() {}
@@ -32,11 +32,6 @@
 
   virtual void Free(void*) {}  // Nop.
 
-  static void* operator new(size_t size, ArenaAlloc* arena) {
-    return arena->Alloc(sizeof(ArenaBitVectorAllocator), kArenaAllocGrowableBitMap);
-  }
-  static void operator delete(void* p) {}  // Nop.
-
  private:
   ArenaAlloc* const arena_;
   DISALLOW_COPY_AND_ASSIGN(ArenaBitVectorAllocator);