RFR: fixing bugs in inference and type system more regression tests [v2]

[Vicente Romero]

> this PR is adapting Types::glb so that it can deal with primitive classes. It also fixes a bug in inference, basically we are now failing during overload resolution if any undetVar has a bound that is a primitive class. But a bug was making inference fail after overload resolution in some cases.

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

 - Merge remote-tracking branch 'refs/remotes/origin/fixing.bugs.in.inference' into fixing.bugs.in.inference
 - fixing bugs in inference and type system

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/654/files
  - new: https://git.openjdk.java.net/valhalla/pull/654/files/860c6726..00ad577c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=654&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=654&range=00-01

  Stats: 8 lines in 1 file changed: 5 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/654.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/654/head:pull/654

PR: https://git.openjdk.java.net/valhalla/pull/654