split debug_assert into ENSURE and ASSERT as discussed in a previous meeting.

the old debug_assert always ran and tested the expression, which slows
down release builds. wrapping them in #ifndef NDEBUG is clumsy. the new
ASSERT behaves like assert and ENSURE like the old debug_assert. Let's
change any time-critical but not-super-important ENSURE to ASSERT to
speed up release builds. (already done in bits.h and unique_range.h)

This was SVN commit r9362.

source/simulation2/scripting/EngineScriptConversions.cpp

@@ -227,7 +227,7 @@ template<> jsval ScriptInterface::ToJSVal<Grid<u16> >(JSContext* cx, const Grid<
 		return JSVAL_VOID;
 
 	js::TypedArray *tdest = js::TypedArray::fromJSObject(darray);
-	debug_assert(tdest->byteLength == len*sizeof(u16));
+	ENSURE(tdest->byteLength == len*sizeof(u16));
 
 	memcpy(tdest->data, val.m_Data, tdest->byteLength);