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

[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.

-------------

Commit messages:
 - fixing bugs in inference and type system

Changes: https://git.openjdk.java.net/valhalla/pull/654/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=654&range=00
  Stats: 36 lines in 3 files changed: 31 ins; 1 del; 4 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