RFR: 8285521: Minor improvements in java.net.URI [v2]

[Сергей Цыпанов]

> - use `String.equalsIgnoreCase()` instead of hand-written code relying on `String.charAt()`
> - use `String.compareToIgnoreCase()` instead of hand-written code relying on `String.charAt()`
> - drop branches that are never executed
> - drop unused argument from `URI.resolvePath()`
> - simplify String-related operations

Сергей Цыпанов has updated the pull request incrementally with one additional commit since the last revision:

  8285521: Revert wrong changes

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8397/files
  - new: https://git.openjdk.java.net/jdk/pull/8397/files/408a3a8e..be41ccf9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8397&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8397&range=00-01

  Stats: 20 lines in 1 file changed: 18 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8397.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8397/head:pull/8397

PR: https://git.openjdk.java.net/jdk/pull/8397