When CLR hasn't been initialized in the process, SOS should mention that when commands fail

[TheJCAB]

This came up during an investigation of SOS-driven debugging of Time Travel Debugging traces. All SOS commands were failing with varied error messages, but the cause for all failures was ultimately the same. GetThreadStoreData failed because the CLR was loaded but not yet initialized in the debugged process.

Before displaying a specific error for a given command, SOS should verify the current status of the relevant process and thread, and display a better, common message if they are not fully initialized.

These are the sorts of errors that were reported, all having ultimately the same root cause of CLR being uninitialized:

0:004> !clrstack
OS Thread Id: 0x4304 (4)
Unable to walk the managed stack. The current thread is likely not a
managed thread. You can run !threads to get a list of managed threads in
the process
Failed to start stack walk: 80070057
0:004> !dumpheap -stat
Error requesting GC Heap data
Unable to build snapshot of the garbage collector state
0:004> !threads
Failed to request ThreadStore
0:004> !mthreads
No supported CLR version found.
WARNING: Unable to register for CLR module notifications

[leculver]

One note here: We always expect ThreadStore data to be placed into well-formed CLR dumps (even down to triage dumps). This means that if the dac request for ThreadStoreData fails we are in one of two situations:

1. The runtime was not initialized. This could be from calling LoadLibrary("clr.dll"); and not doing anythign with it, for example, or even just that the process crashed or was stopped before we got through enough of the initialization of CLR to set ThreadStore::s_pThreadStore.
2. The crash dump was taken without calling into our EnumMemRegions helper.

Adding a helper function to SOS which calls GetThreadStoreData and then printings a message if it fails with the above info should help eliminate confusion.