Always end preprocessor expression processing at end of line.

In certain error cases, tokens from subsequent lines could get treated as part of a preprocessor expression, causing subsequent code to be essentially ignored and producing strange error messages.

Here is an example (with an error) affected by this:

#pragma optimize 0 0
int main(void) {}

Scanner.pas

@@ -2342,7 +2342,7 @@ var
    begin {NumericDirective}
    doingPPExpression := true;
    NextToken;                            {skip the directive name}
-   Expression(preprocessorExpression, []); {evaluate the expression}
+   Expression(preprocessorExpression, [eolsy]); {evaluate the expression}
    doingPPExpression := false;
    end; {NumericDirective}