1.30 beta.7 const-related tests fails on multiple architectures

[infinity0]

arch	const-eval/double_check{,2}	const-size_of-cycle	invalid_const_promotion
armv7-hf	ok	failed	ok
aarch64	ok	failed	failed
ppc64	failed	failed	failed
s390x	failed	failed	ok

[karcherm]

const-eval/double_check (and its sibling) fail on all Big-Endian architectures, because the Enums are not represented in usize, so casting a pointer to the usize-constant 5 or 42 does not yield a pointer to a (probably u8-sized) Enum with the value 5 or 42, but the value 0 instead, as Big-Endian architectures have the more significant bytes containing 0x00 before the interesting byte containing 5 or 42.

[karcherm]

This has already been fixed in HEAD by 283f2be.

[oli-obk]

ah, this only fixes the enum test. So const-size_of-cyle and invalid_const_promotion still need fixing