function parameters no more considered as IN_FUNCTION

Separate the parameters of a function from the processing of the body.

In a code like:

 function foo( $var1, $var2 ) {
   $var3 = 2;
 }

Everything from '$var1' to the final '}' was IN_FUNCTION. This commit
separate processing of the function parameters so they are no more
considered as part of the body (aka IN_FUNCTION).

Change-Id: I34c7d2c53025d241a944064302eb62f985005914