Use OverflowError exception type for overflows

Initially I used one of the existing exception raise functions, but it's
more correct and not much more code to raise OverflowError instead.

Author: Matt Wozniski

py/objint.c

@@ -340,7 +340,7 @@ void mp_obj_int_buffer_overflow_check(mp_obj_t self_in, size_t nbytes, bool is_s
     return;
 
 raise:
-    mp_raise_ValueError_varg(translate("value would overflow a %d byte buffer"), nbytes);
+    mp_raise_OverflowError_varg(translate("value would overflow a %d byte buffer"), nbytes);
 }
 
 #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE

py/runtime.c

@@ -1598,6 +1598,14 @@ NORETURN void mp_raise_NotImplementedError_varg(const compressed_string_t *fmt,
     nlr_raise(exception);
 }
 
+NORETURN void mp_raise_OverflowError_varg(const compressed_string_t *fmt, ...) {
+    va_list argptr;
+    va_start(argptr,fmt);
+    mp_obj_t exception = mp_obj_new_exception_msg_vlist(&mp_type_OverflowError, fmt, argptr);
+    va_end(argptr);
+    nlr_raise(exception);
+}
+
 NORETURN void mp_raise_MpyError(const compressed_string_t *msg) {
     mp_raise_msg(&mp_type_MpyError, msg);
 }

py/runtime.h

@@ -163,6 +163,7 @@ NORETURN void mp_raise_OSError_msg(const compressed_string_t *msg);
 NORETURN void mp_raise_OSError_msg_varg(const compressed_string_t *fmt, ...);
 NORETURN void mp_raise_NotImplementedError(const compressed_string_t *msg);
 NORETURN void mp_raise_NotImplementedError_varg(const compressed_string_t *fmt, ...);
+NORETURN void mp_raise_OverflowError_varg(const compressed_string_t *fmt, ...);
 NORETURN void mp_raise_MpyError(const compressed_string_t *msg);
 NORETURN void mp_raise_recursion_depth(void);