RFR: 8349705: java.net.URI.scanIPv4Address throws unnecessary URISyntaxException [v2]

[Xiaolong Peng]

> java.net.URI.scanIPv4Address is a private method, it is only called by java.net.URI.takeIPv4Address and java.net.URI.parseIPv4Address, the URISyntaxException("Malformed IPv4 address") is not necessary, returning -1 should be good. In one of our systems, we noticed the exception consumes ~0.3% CPU.
> 
> Additional test:
> - [x] make test TEST=jdk/java/net

Xiaolong Peng has updated the pull request incrementally with one additional commit since the last revision:

  Address PR comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/23538/files
  - new: https://git.openjdk.org/jdk/pull/23538/files/fe26481f..be5bedd2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23538&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23538&range=00-01

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23538.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23538/head:pull/23538

PR: https://git.openjdk.org/jdk/pull/23538