MDEV-34502 InnoDB debug mode build - asserts with Valgrind

Valgrind looks as the assertions as examining uninitalized values.

As the assertions are tested in other Debug builds we know
it isn't all invalid.

Account for Valgrind by removing the assertion under
the WITH_VALGRIND=1 compulation.

storage/innobase/include/mach0data.inl

@@ -38,7 +38,9 @@ mach_write_to_1(
 	byte*	b,	/*!< in: pointer to byte where to store */
 	ulint	n)	/*!< in: ulint integer to be stored, >= 0, < 256 */
 {
+#ifndef HAVE_valgrind
 	ut_ad((n & ~0xFFUL) == 0);
+#endif
 
 	b[0] = (byte) n;
 }
@@ -55,7 +57,9 @@ mach_write_to_2(
 	byte*	b,	/*!< in: pointer to two bytes where to store */
 	ulint	n)	/*!< in: ulint integer to be stored */
 {
+#ifndef HAVE_valgrind
 	ut_ad((n & ~0xFFFFUL) == 0);
+#endif
 
 	b[0] = (byte)(n >> 8);
 	b[1] = (byte)(n);