RFR: type of TypeVar.ref is incorrect and should be fixed [v6]

[Vicente Romero]

> The type of TypeVar.ref is incorrect and should be fixed, in particular due to a bug, the compiler is not able to differentiate between  `T` and `T.ref` which should have a different type

Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:

  removing whitespace

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/658/files
  - new: https://git.openjdk.java.net/valhalla/pull/658/files/4d9379db..2b4f4416

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=658&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=658&range=04-05

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/658.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/658/head:pull/658

PR: https://git.openjdk.java.net/valhalla/pull/658