Recently I was debugging a Minidump with a few thousand ranges, and came
across the (now deleted) comment:
```
// I don't have a sense of how frequently this is called or how many memory
// ranges a Minidump typically has, so I'm not sure if searching for the
// appropriate range linearly each time is stupid. Perhaps we should build
// an index for faster lookups.
```
blaming this comment, it's 9 years old! Much overdue for this simple fix
with a range data vector.
I had to add a default constructor to Range in order to implement the
RangeDataVector, but otherwise this just a replacement of look up logic.
a96a3f1b26