RFR: bug: no warning shown for parameterized conversions [v3]

[Vicente Romero]

> no warning is shown for parameterized conversions

Vicente Romero has updated the pull request incrementally with three additional commits since the last revision:

 - refactorings, code cleanup
 - minor bug fix
 - parameterizing type rutines for universal tvars

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/666/files
  - new: https://git.openjdk.java.net/valhalla/pull/666/files/41ac982e..12188626

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=666&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=666&range=01-02

  Stats: 118 lines in 1 file changed: 81 ins; 18 del; 19 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/666.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/666/head:pull/666

PR: https://git.openjdk.java.net/valhalla/pull/666