Summary
-------

Define additional diagnostic commands, in order to improve the diagnosability of
Hotspot and the JDK.


Description
-----------

This is a list of the new commands (exact names are TBD):

### `print_class_summary`
 - Print a list of all loaded classes and their inheritence structure.
 - Responsible group: runtime

### `print_codegenlist`
  - Print methods queued for compilation with either C1 or C2 (separate
    queues)
  - Responsible group: compiler
 
### `print_utf8pool`
 - Print all UTF-8 string constants.
 - Responsible group: runtime

### `datadump_request`
 - Signal the JVM to do a data-dump request for JVMTI.
 - Responsible group: serviceability

### `dump_codelist`
 - Print n-methods (compiled) with full signature, address range, and state
   (alive, nonentrant, and zombie).
 - Allow selection of printing to stdout or to a file.
 - Allow XML or text printout.
 - Responsible group: compiler

### `print_codeblocks `
 - Print the size of the code cache and a list of blocks in the code
   cache, with adresses.
 - Responsible group: compiler

### `set_vmflag`
 - Set a command-line flag/option in VM or the libraries.
 - Responsible group: servicability


Testing
-------

There needs to be a test for each command to verify the output.