[Issue 21919] darwin: SEGV in core.thread tests on OSX 11

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21919

--- Comment #7 from Lionello Lunesu <lio+bugzilla at lunesu.com> ---
Stack trace for previous crash:

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS
(code=2, address=0x1001e9c60)
  * frame #0: 0x00007fff2031b4a8 libsystem_pthread.dylib`___chkstk_darwin + 96
    frame #1: 0x00007fff2031b448 libsystem_pthread.dylib`thread_start + 20
    frame #2: 0x00007fff2a4bfb2d
libunwind.dylib`libunwind::UnwindCursor<libunwind::LocalAddressSpace,
libunwind::Registers_x86_64>::getInfoFromDwarfSection(unsigned long,
libunwind::UnwindInfoSections const&, unsigned int) + 191
    frame #3: 0x00007fff2a4bfa01
libunwind.dylib`libunwind::UnwindCursor<libunwind::LocalAddressSpace,
libunwind::Registers_x86_64>::setInfoBasedOnIPRegister(bool) + 999
    frame #4: 0x00007fff2a4c1ec9
libunwind.dylib`libunwind::UnwindCursor<libunwind::LocalAddressSpace,
libunwind::Registers_x86_64>::step() + 461
    frame #5: 0x00007fff2a4c3a18 libunwind.dylib`_Unwind_RaiseException + 189
    frame #6: 0x000000010002fca5 test15779_0`_d_throwdwarf + 185
    frame #7: 0x0000000100002410
test15779_0`_D9test157793barFZ9__lambda1FNaNfZv + 80
    frame #8: 0x000000010002cc2f
test15779_0`_D4core6thread7context8Callable6opCallMFZv + 27
    frame #9: 0x00000001000293a7 test15779_0`fiber_entryPoint + 99

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