M68k's SETCC instruction (`scc`) distinctly fills the destination byte
with all 1s. If boolean contents are set to `ZeroOrOneBooleanContent`,
LLVM can mistakenly think the destination holds `0x01` instead of `0xff`
and emit broken code as a result. This change corrects the boolean
content type to `ZeroOrNegativeOneBooleanContent`.

For example, this IR:

```llvm
define dso_local signext range(i8 0, 2) i8 @testBool(i32 noundef %a) local_unnamed_addr #0 {
entry:
  %cmp = icmp eq i32 %a, 4660
  %. = zext i1 %cmp to i8
  ret i8 %.
}
```

would previously build as:

```asm
testBool:                               ; @testBool
	cmpi.l	#4660, (4,%sp)
	seq	%d0
	and.l	#255, %d0
	rts
```

Notice the `zext` is erroneously not clearing the low bits, and thus the
register returns with 255 instead of 1. This patch fixes the issue:

```asm
testBool:                               ; @testBool
	cmpi.l	#4660, (4,%sp)
	seq	%d0
	and.l	#1, %d0
	rts
```

Most of the tests containing `scc` suffered from the same value error as
described above, so those tests have been updated to match the new
output (which also logically corrects them).