Whitelist aLogger, in FormulaLogger& FormulaLogger::get()

To avoid this:

sc/source/core/tool/formulalogger.cxx:55:26: error: bad static variable causes crash on shutdown [loplugin:badstatics]
    static FormulaLogger aLogger;
    ~~~~~~~~~~~~~~~~~~~~~^~~~~~~
sc/inc/formulalogger.hxx:42:31: note: ... due to this member of 'FormulaLogger' [loplugin:badstatics]
    const ScFormulaCellGroup* mpLastGroup = nullptr;
    ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
sc/inc/formulacell.hxx:66:20: note: ... due to this member of 'ScFormulaCellGroup' [loplugin:badstatics]
    ScFormulaCell *mpTopCell;
    ~~~~~~~~~~~~~~~^~~~~~~~~
sc/inc/formulacell.hxx:114:21: note: ... due to this member of 'ScFormulaCell' [loplugin:badstatics]
    ScDocument*     pDocument;
    ~~~~~~~~~~~~~~~~^~~~~~~~~
sc/inc/document.hxx:312:27: note: ... due to this member of 'ScDocument' [loplugin:badstatics]
    VclPtr<SfxPrinter>    pPrinter;
    ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~

Change-Id: I533e45f655ca928a801188aa48ee818d89a962ac

compilerplugins/clang/badstatics.cxx

@@ -197,6 +197,7 @@ public:
                     // ScAddInAsync* keys if that set is not empty at exit
                 || name == "g_aWindowList"
                     //vcl/unx/gtk/a11y/atkutil.cxx, asserted empty at exit
+                || name == "aLogger" // FormulaLogger& FormulaLogger::get() in sc/source/core/tool/formulalogger.cxx
                 || (loplugin::DeclCheck(pVarDecl).Var("aAllListeners")
                     .Class("ScAddInListener").GlobalNamespace()) // not owning
                ) // these variables appear unproblematic