RFR: 8278860: Streamline properties for Monocle [v2]

[Johan Vos]

> Base decisions in prism for embedded cases on the same glass.platform property that is also used in glass.
> This PR replaces the property `embedded` with the property `glass.platform` .
> 
> There is only 1 place where the property `embedded` was read, which is in the PlatformUtil.java.
> 
> There are only 2 places where the value of that property is used, and in both cases the only check is to detect whether or not that property has a value of "monocle".

Johan Vos has updated the pull request incrementally with one additional commit since the last revision:

  Add space after comma

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Changes:
  - all: https://git.openjdk.java.net/jfx/pull/696/files
  - new: https://git.openjdk.java.net/jfx/pull/696/files/00146dd1..a0af3c6b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=696&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=696&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/696.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/696/head:pull/696

PR: https://git.openjdk.java.net/jfx/pull/696