ConstProp RemoveUselessMasking pass breaks 8-bit test/jnz
In an application's use of zlib 1.2.3 (inflate_fast) compiled with MSVC, the following basic block is observed:

```asm
mov     r11d, [r9+rax*4]
mov     eax, r11d
movzx   edx, r11b
shr     eax, 8
movzx   ecx, al
shr     ebx, cl
sub     r10d, ecx
test    r11b, r11b
jnz     short loc_141284962
```

However, the following IR is generated for the test/jcc:

```
                %ssa45(GPR0) i64 = Select %ssa11(GPR0) i32, %ssa42(Invalid4294967295), %ssa43(Invalid4294967295), %ssa44(Invalid4294967295), EQ, #0x8
                (%ssa46 i0) StoreFlag %ssa45(GPR0) i64, #0x6
                %ssa47(GPR1) i64 = Constant #0x0
                (%ssa48 i0) StoreFlag %ssa47(GPR1) i64, #0x0
                %ssa49(GPR1) i64 = Constant #0x0
                (%ssa50 i0) StoreFlag %ssa49(GPR1) i64, #0xb
                (%ssa51 i0) InlineConstant #0x0
                (%ssa52 i0) CondJump %ssa45(GPR0) i64, %ssa51(Invalid4294967295), %ssa3(Invalid4294967295), %ssa4(Invalid4294967295), EQ, #0x8
                (%ssa53 i0) EndBlock %ssa2(Invalid4294967295)
```

`r11d` at this time contained a value `0x00410400`, which leads to the jump being incorrectly taken, for a 32-bit compare-to-zero is used as a jump condition.