RTL fixes + few small bugs

1. Removed unnecessary iterators (use SkShaper iterators instead)
2. More careful hash function and comparison (ParagraphStyle)
3. computeEmptyMetrics should go after resolveStrut
4. longestLine for line with spaces only should not be 0
5. LTR/RTL * left/right align * latin/arabic * leading/trailing spaces positioning
6. Height for MaxHeight rect (to follow Gary's change)

Change-Id: I3507ff9fb93148e5ef882a2f514078fcea9cfef3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268301
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Julia Lavrova <jlavrova@google.com>
10 files changed