RFR: 8281266: [JVMCI] MetaUtil.toInternalName() doesn't handle hidden classes correctly [v2]

[Foivos]

> https://github.com/openjdk/jdk/commit/7cc137105928ec109a29d9315565f7f49af3cf2b introduced hidden classes with internal names like `com/example/Foo.1234` that get changed to `com.example.Foo/1234` by `Class.getName()` which are not properly handled by `MetaUtil`'s `toInternalName` and `internalNameToJava`
> 
> This PR fixes this along with the corresponding test that used to work on the assumption that the internal class names didn't contain the `.` character and that java class names didn't contain the `/` character except for lambdas (which are now treated as hidden classes as well), an assumption that no longer holds.

Foivos has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  Fix handling of hidden classes in MetaUtil
  
  7cc137105928ec109a29d9315565f7f49af3cf2b introduced hidden classes with
  internal names like com/example/Foo.1234 that get changed to
  com.example.Foo/1234 by Class.getName() which are not properly handled
  by MetaUtil's toInternalName and internalNameToJava

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7346/files
  - new: https://git.openjdk.java.net/jdk/pull/7346/files/90934723..f0ac427c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7346&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7346&range=00-01

  Stats: 17 lines in 1 file changed: 12 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7346.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7346/head:pull/7346

PR: https://git.openjdk.java.net/jdk/pull/7346