incorrect alignment of constants

[andrewrk]

const std = @import("std");

test "aou" {
    const x: f32 align(128) = 12.34;
    std.debug.assert(@ptrToInt(&x) % 128 == 0);
}

Test 1/1 aou...assertion failure

[andrewrk]

Fixed in master, regression test added, and I confirmed the const in the LLVM IR is getting the alignment:

@0 = internal unnamed_addr constant float 0x4028AE1480000000, align 128