RFR: 6434110: Color constructor parameter name is misleading [v2]

[Sergey Bylokhov]

> Small cleanup: the parameter names in the Color(int, boolean) constructor have been renamed:
>  - rgba -> argb, since this is the format described in the spec
>  - hasalpha -> hasAlpha, to follow common naming conventions
> 
> Also adds a basic test for the constructor.

Sergey Bylokhov has updated the pull request incrementally with one additional commit since the last revision:

  review feedback

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29734/files
  - new: https://git.openjdk.org/jdk/pull/29734/files/1752fdff..3ae10ac3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29734&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29734&range=00-01

  Stats: 10 lines in 2 files changed: 0 ins; 1 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/29734.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29734/head:pull/29734

PR: https://git.openjdk.org/jdk/pull/29734