Fix some issues reported by Valgrind

* Update the target suppression file.
* Disable the detection of mismatched free() / delete / delete []
calls, since it results in a lot of false positives (a known
Valgrind limitation associated with asymmetric inlining of
operator new() and operator delete()).
* Avoid a memory leak in the code generator tests, caused by the
fact that the VIXL-based ARM code generator does not always use
the arena allocator.
* Fix an access to uninitialized memory.

Test: m valgrind-test-art-target
Test: valgrind --leak-check=full --show-mismatched-frees=no \
               --ignore-range-below-sp=1024-1 \
               --suppressions=valgrind-target-suppressions.txt \
               dalvikvm ...
Change-Id: I891a3247aa9828226b4e62c69d6e1c8398d757b8
diff --git a/compiler/optimizing/codegen_test.cc b/compiler/optimizing/codegen_test.cc
index 879b4ce..e3f3df0 100644
--- a/compiler/optimizing/codegen_test.cc
+++ b/compiler/optimizing/codegen_test.cc
@@ -15,6 +15,7 @@
  */
 
 #include <functional>
+#include <memory>
 
 #include "arch/instruction_set.h"
 #include "arch/arm/instruction_set_features_arm.h"
@@ -299,8 +300,8 @@
                     bool has_result,
                     Expected expected) {
   CompilerOptions compiler_options;
-  CodeGenerator* codegen = target_config.CreateCodeGenerator(graph, compiler_options);
-  RunCode(codegen, graph, hook_before_codegen, has_result, expected);
+  std::unique_ptr<CodeGenerator> codegen(target_config.CreateCodeGenerator(graph, compiler_options));
+  RunCode(codegen.get(), graph, hook_before_codegen, has_result, expected);
 }
 
 #ifdef ART_ENABLE_CODEGEN_arm