Remove unused variable and tidy test #includes.

Change-Id: I0eaeea0d50f66302d632aab400cfa48dc301ef69
diff --git a/runtime/jni_internal_test.cc b/runtime/jni_internal_test.cc
index 7b29a9c..071b658 100644
--- a/runtime/jni_internal_test.cc
+++ b/runtime/jni_internal_test.cc
@@ -16,17 +16,9 @@
 
 #include "jni_internal.h"
 
-#include <limits.h>
-#include <cfloat>
-#include <cmath>
-
 #include "common_compiler_test.h"
 #include "mirror/art_method-inl.h"
-#include "mirror/class-inl.h"
-#include "mirror/object_array-inl.h"
-#include "mirror/object-inl.h"
 #include "ScopedLocalRef.h"
-#include "sirt_ref.h"
 
 namespace art {
 
diff --git a/runtime/reflection_test.cc b/runtime/reflection_test.cc
index c14da5d..5332202 100644
--- a/runtime/reflection_test.cc
+++ b/runtime/reflection_test.cc
@@ -16,7 +16,7 @@
 
 #include "reflection.h"
 
-#include <cmath>
+#include <limits.h>
 
 #include "common_compiler_test.h"
 #include "mirror/art_method-inl.h"
diff --git a/runtime/thread.cc b/runtime/thread.cc
index f5ed082..afa5574 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -1559,7 +1559,6 @@
 
   // Choose an appropriate constructor and set up the arguments.
   const char* signature;
-  const char* shorty;
   ScopedLocalRef<jstring> msg_string(GetJniEnv(), nullptr);
   if (msg != nullptr) {
     // Ensure we remember this and the method over the String allocation.
@@ -1570,18 +1569,14 @@
       return;
     }
     if (cause.get() == nullptr) {
-      shorty = "VL";
       signature = "(Ljava/lang/String;)V";
     } else {
-      shorty = "VLL";
       signature = "(Ljava/lang/String;Ljava/lang/Throwable;)V";
     }
   } else {
     if (cause.get() == nullptr) {
-      shorty = "V";
       signature = "()V";
     } else {
-      shorty = "VL";
       signature = "(Ljava/lang/Throwable;)V";
     }
   }