Fixes Android build by using C++ math header instead of C one.

runtime/vm/assembler_mips_test.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/os.h"
@@ skipping 1621 matching lines @@
   __ mtc1(T0, F3);  // Load lower bits of NaN.
   __ addd(D0, D0, D1);
   __ Ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Addd_NaN, test) {
   typedef double (*SimpleCode)() DART_UNUSED;
   EXPECT(test != NULL);
   double res = EXECUTE_TEST_CODE_DOUBLE(SimpleCode, test->entry());
-  EXPECT_EQ(isnan(res), true);
+  EXPECT_EQ(std::isnan(res), true);
 }
 
 
 ASSEMBLER_TEST_GENERATE(Addd_Inf, assembler) {
   __ LoadImmediate(D0, 1.0);
   __ LoadImmediate(T0, 0x7FF00000);  // +inf
   __ mtc1(ZR, F2);
   __ mtc1(T0, F3);
   __ addd(D0, D0, D1);
   __ Ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Addd_Inf, test) {
   typedef double (*SimpleCode)() DART_UNUSED;
   EXPECT(test != NULL);
   double res = EXECUTE_TEST_CODE_DOUBLE(SimpleCode, test->entry());
-  EXPECT_EQ(isfinite(res), false);
+  EXPECT_EQ(std::isfinite(res), false);
 }
 
 
 ASSEMBLER_TEST_GENERATE(Subd, assembler) {
   __ LoadImmediate(D0, 2.5);
   __ LoadImmediate(D1, 1.5);
   __ subd(D0, D0, D1);
   __ Ret();
 }
 
@@ skipping 391 matching lines @@
                      A1);
   __ lw(RA, Address(SP, 0 * kWordSize));
   __ lw(CTX, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS