advapi32/tests: Check that a credential type is supported before testing it. Test CRED_TYPE_DOMAIN_VISIBLE_PASSWORD credentials. Factorize the CredentialBlob checks.

systray: Avoid modifying non-existent tooltip windows of non-existent icon windows when application updates tip of hidden icon.

shell32: Memory allocated by CommandLineToArgvW should be that got from LocalAlloc/LocalReAlloc, not from GlobalAlloc.

Use LMEM_FIXED instead of 0 in calls to LocalAlloc to emphasise that 
we're getting a direct pointer, not a handle to memory.

Remove hargv as it is confusing and unnecessary.

shlwapi: IID_IInternetSecurityMgrSite is now defined so remove the local definition from IUnknown_GetWindow.

dxdiagn: Fix the character count passed to snprintfW in DXDiag_AddFileDescContainer and DXDiag_InitDXDiagDisplayContainer.

dbghelp: Fix a typo in SymLoadModuleExW that caused the wrong number of characters to be passed to lstrcpynW.

advapi32: The lpcbSecurityDescriptor parameter to RegGetKeySecurity isn't optional, so don't complicate the code by treating as though it is.