Refactor _swift_withWin32DbgHelpLibrary() to avoid using GetCurrentProcess() per Microsoft documentation

[grynspan]

The Microsoft documentation for the DbgHelp library warns developers not to pass GetCurrentProcess() as the handle to SymInitialize() etc.

This change uses a privately-held handle duplicated from GetCurrentProcess(). It also takes care to set DbgHelp library options consistently in case something elsewhere calls SymSetOptions() and sets them to something incompatible with the runtime's expectations.

We still have no way to thread-safely use the library in coordination with code outside the runtime, but at least the runtime should avoid stomping on shared system resources.

Resolves #62290.

[grynspan]

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@swift-ci please test windows

[compnerd]

I don't think I ever noticed the fine print there. This is terrifying, this is terrible, and we should feel bad. Thanks for this fix, sorry for any scars that it may have inflicted upon you.

[al45tair]

I particularly enjoy this part (emphasis mine):

[in] hProcess

A handle that identifies the caller. This value should be unique and nonzero, but need not be a process handle.

So, they called it hProcess and gave it the type HANDLE, but it can actually be any unique value.

Maybe we'd be better off just casting the address of something to HANDLE and passing that, since that will be unique and means we don't need to worry about DuplicateHandle() failing.

[grynspan]

That comment lies. If you pass some other address with fInvadeProcess = true then SymInitialize() succeeds but symbolication with SymFromAddr() fails with error ERROR_MOD_NOT_FOUND.

I suspect UnDecorateSymbolName() would work in that scenario since it doesn't take a handle argument, but I haven't tested it specifically.

[al45tair]

That comment lies. If you pass some other address with fInvadeProcess = true then SymInitialize() succeeds but symbolication with SymFromAddr() fails with error ERROR_MOD_NOT_FOUND.

Joy 😂

[grynspan]

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