Merge "Remove the weird range variants of String8::toLower() and String8::toUpper()." am: 561209ee66 am: 7e7ff3635d

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1670567

Change-Id: I397edfff4cd96c30aba03c5960be5473bb19333b