RFR: 8278863: Add method ClassDesc::ofInternalName [v6]

[Adam Sotona]

> The symbolic constants API (`java.lang.constant`) was designed, in part, to provide bytecode parsing and generation APIs with a validated, common, symbolic form for constants in Java class files. 
> 
> There is an easy way to create a `ClassDesc` from a binary name (`ClassDesc::of`) or a field descriptor (`ClassDesc::ofDescriptor`) but not from an internal name. But, the internal name is common in low-level bytecode-manipulation code. 
> 
> This patch adds `ClassDesc::ofInternalName` static factory method that creates a `ClassDesc` from class internal name.
> Class internal name validation and extended ClassDescTest are also parts of this patch.
> 
> CSR is linked with the issue.
> 
> Please review.
> 
> Thank you,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  javadoc fixes

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9201/files
  - new: https://git.openjdk.org/jdk/pull/9201/files/b25351c1..1790cf29

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9201&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9201&range=04-05

  Stats: 10 lines in 1 file changed: 8 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9201.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9201/head:pull/9201

PR: https://git.openjdk.org/jdk/pull/9201