Range Analysis: Compute the range of loop control variable - Part III

This patch implements the range analysis on the loop control variable
of a simple for-loop when the for-loop matches the below pattern:

```
// The range of i is [const_rhs, const_value]
for (var i = const_value; const_rhs <= i; i--)

// The range of i is [const_value, const_rhs]
for (var i = const_value; const_rhs >= i; i++)

// The range of i is [const_rhs + 1, const_value]
for (var i = const_value; const_rhs < i; i--)

// The range of i is [const_value, const_rhs - 1]
for (var i = const_value; const_rhs > i; i++)
```

Bug: 348701956
Test: tint_unittests
Change-Id: Id95c7d4ae62333731a6641e0261d60077d321592
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/238234
Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>
Reviewed-by: James Price <jrprice@google.com>