Exception throwing/handling is broken

[Jan Vraný]

Exception handling / throwing is broken. Whenever an exception
is thrown, a context linenumber has to be set up properly in order
to find handler.

This is a problem especially for jitted code as it resorts to
caling helper functions like _throw() or _ldiv(). These functions
has to take current bytecode PC as argument.

The testcases should include something like

ex = new ArithmeticException("test");
try {
    throw ex;
    fail();
} catch (ArithmeticException ae) {
    // OK
} catch (Exception e) {
    fail();
}

and of course

int i1 = 10;
int i2 = 0;
try {
    int r = i1 / i2;
    fail();
} catch (ArithmeticException ae) {
    // OK
} catch (Exception e) {
    fail();
}