[Bug 55379] New: kernel32:loader sometimes gets a bad thread count on Windows 10 in phase 0/1

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55379

Bug ID: 55379
           Summary: kernel32:loader sometimes gets a bad thread count on
                    Windows 10 in phase 0/1
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: [e-mail]
          Reporter: [e-mail]

kernel32:loader sometimes gets a bad thread count on Windows 10 in phase 0/1.
So far there are only two instances, both in the 64-bit tests:

* 2023-07-31 w1064-adm 64-bit tests
  loader.c:2875: phase 1: writing 00007FF633B64570 at 0x202
  loader.c:2514: dll: 0000000010000000, DLL_PROCESS_ATTACH, 0000000000000000
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2399: 1eb0: mutex_thread_proc: starting
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2954: Test failed: attached thread count should be 2

* 2023-06-07 fgtb-w10pro64 64-bit tests
  loader.c:2875: phase 0: writing 000000000048FED0 at 0x202
  loader.c:2514: dll: 0000000010000000, DLL_PROCESS_ATTACH, 0000000000000000
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2399: 1414: mutex_thread_proc: starting
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2784: dll: 0000000010000000, DLL_THREAD_ATTACH, 0000000000000000
  loader.c:2954: Test failed: attached thread count should be 2

See https://test.winehq.org/data/patterns.html#kernel32:loader