Run InvokeWrappingPass before AllocaLoweringPass

[DutChen18]

When rewriting calls to variadic functions, AllocaLowering only handles call instructions, not invoke instructions. By moving InvokeWrapping before AllocaLowering, the problematic invokes are converted to calls before AllocaLowering is run.

This fixes an issue with exceptions and variadic arguments:

extern "C" {
        int printf(const char *__restrict, ...);
}
struct Struct
{
        static void func();
};

class ArgParse {
public:
        ~ArgParse ();
        int options (const char *intro, ...) /*noexcept*/;
};

int ArgParse::options (const char *intro, ...) /*noexcept*/
{
        __builtin_va_list ap;
        __builtin_va_start(ap, intro);
        const char *cur = __builtin_va_arg(ap, char *);
        printf("Variadic %s\n", cur);
        Struct::func();
        return 0;
}

void webMain()
{
        ArgParse ap;
        ap.options ("", "__GOOD__");
}

/opt/cheerp/bin/clang++ --target=cheerp-wasm -O2 -o test.js test.cpp -cheerp-pretty-code -fexceptions && nodejs test.js

Before: Variadic (null)
After: Variadic __GOOD__