Speed up blame tests by filtering non-.NET processes from dump collection

[nohwnd]

Summary

Speeds up blame/hang dump tests by filtering out non-.NET processes (\conhost, \WerFault, \createdump) from the process tree before attempting dump collection. This avoids the 30s DiagnosticsClient timeout that occurs when trying to connect to native processes.

Also fixes the implicit full hang dump in \CrashDumpWhenThereIsNoTimeout\ and reduces child process tree depth.

Changes

• *\NetClientHangDumper.cs* — filter \conhost/\WerFault/\createdump\ from process tree (fixes the 30s timeout per non-.NET process)
• *\WindowsHangDumper.cs* — add \createdump\ to existing filter
• *\BlameDataCollectorTests.cs* — add \HangDumpType=mini\ where it defaulted to Full
• *\child-hang/child-crash* — reduce process tree from 3→2 children

Results

Test	Before	After	Savings
\HangDumpChildProcesses\	39.4s	16.1s	59%
\CrashDumpChildProcesses\	32.3s	17.9s	45%
\CrashDumpWhenThereIsNoTimeout\ (2 variants)	62.4s	39.7s	36%