Cleanup regex diagnostic output

[danmoseley]

Updates to the diagnostic output you get if you pass RegexOptions.Debug and have a debug-build of System.Text.RegularExpressions.dll

• Log the pattern itself
• Fix an actual bug in the char class output - introduced long ago when the implementation was changed, but the dumping was not. Generate the table from the implementation instead.
• Change Boyer-Moore logging to fewer lines: it's only interesting if there's a bug in B-M, probably.
• Improve the indenting and spacing of the node and code trees.

Example:

[8340] Pattern:     (abc|de){2,11}
[8340] Capture                  index = 0 
[8340]   Loop                     min = 2, max = 11 
[8340]     Capture                  index = 1 
[8340]       Alternate                 
[8340]         Multi                    abc 
[8340]         Multi                    de 
[8340] Direction:  left-to-right 
[8340] Firstchars: [ad] 
[8340] Prefix:     n/a 
[8340] Anchors:    None 
[8340]  
[8340] 000000 *Lazybranch       addr = 23 
[8340] 000002 *Setmark           
[8340] 000003 *Setcount         value = -1 
[8340] 000005 *Setmark           
[8340] 000006 *Lazybranch       addr = 12 
[8340] 000008  Multi            abc 
[8340] 000010 *Goto             addr = 14 
[8340] 000012  Multi            de 
[8340] 000014 *Capturemark      index = 1 
[8340] 000017 *Branchcount      addr = 5, limit = 9 
[8340] 000020 *Capturemark      index = 0 
[8340] 000023  Stop              

I did not change the execution logging, although that's very verbose and possibly ought to have a separate toggle.

And boo to all apps that ship and don't remove their debug output! I've opened bugs against VS in the past for this, they've fixed them and now I've another to open. Although, that's not the worst culprit.

[danmoseley]

cc @pgovind

[danmoseley]

OK now?

[danmoseley]

Also noticed RegexParser.RightChar could be private.