Fix initial FPSCR state in ARM simulator

Rounding mode should be round-to-nearest by default, and NaN mode bit
should be 0, like in a real ARM system.

BUG=3253
LOG=N
R=rmcilroy@chromium.org

Review URL: https://codereview.chromium.org/235893005

Patch from Olli Etuaho <oetuaho@nvidia.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20725 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/simulator-arm.cc

@@ -773,8 +773,8 @@ Simulator::Simulator(Isolate* isolate) : isolate_(isolate) {
   z_flag_FPSCR_ = false;
   c_flag_FPSCR_ = false;
   v_flag_FPSCR_ = false;
-  FPSCR_rounding_mode_ = RZ;
-  FPSCR_default_NaN_mode_ = true;
+  FPSCR_rounding_mode_ = RN;
+  FPSCR_default_NaN_mode_ = false;
 
   inv_op_vfp_flag_ = false;
   div_zero_vfp_flag_ = false;