Add noexcept specifier to placement new operator

The standard mandates that placement new should be have a noexcept specifier.

cores/arduino/new.cpp

@@ -26,7 +26,7 @@ void *operator new[](size_t size) {
   return malloc(size);
 }
 
-void * operator new(size_t size, void * ptr) {
+void * operator new(size_t size, void * ptr) noexcept {
   (void)size;
   return ptr;
 }

cores/arduino/new.h

@@ -23,7 +23,7 @@
 
 void * operator new(size_t size);
 void * operator new[](size_t size);
-void * operator new(size_t size, void * ptr);
+void * operator new(size_t size, void * ptr) noexcept;
 void operator delete(void * ptr);
 void operator delete[](void * ptr);