Rename BadNumberFormatException -> FormatException.

runtime/lib/math.cc

Index: runtime/lib/math.cc
diff --git a/runtime/lib/math.cc b/runtime/lib/math.cc
index 851fdad6737186c8930a256d9146dc9b39f8b731..32e8ebc408626288a76fa2941dec71f301327ee9 100644
--- a/runtime/lib/math.cc
+++ b/runtime/lib/math.cc
@@ -124,7 +124,7 @@ DEFINE_NATIVE_ENTRY(MathNatives_parseInt, 1) {
   } else {
     GrowableArray<const Object*> args;
     args.Add(&value);
-    Exceptions::ThrowByType(Exceptions::kBadNumberFormat, args);
+    Exceptions::ThrowByType(Exceptions::kFormat, args);
   }
 }
 
@@ -176,7 +176,7 @@ DEFINE_NATIVE_ENTRY(MathNatives_parseDouble, 1) {
 
   GrowableArray<const Object*> args;
   args.Add(&value);
-  Exceptions::ThrowByType(Exceptions::kBadNumberFormat, args);
+  Exceptions::ThrowByType(Exceptions::kFormat, args);
 }
 
 }  // namespace dart