Rename main objects in tests to _main

This was done just because compiling with a non-empty classpaths leads
to conflicts when main is used as an annotation.

Author: odersky

tests/fuzzy/b82054893e0db44e31ae82d696c19c1fbc7be55c.scala

@@ -1,4 +1,4 @@
-object main {
+object _main {
 def i0 = {
 class i1 {
 private[i0] var i2: _ > 0 private def i3: List[Int]

tests/pos/localmodules.scala

@@ -1,6 +1,6 @@
 package test;
 
-object main {
+object _main {
 
   class a {
 

tests/pos/t0002.scala

@@ -1,4 +1,4 @@
-object main {
+object _main {
   def main(args: Array[String]) = {
     val b = true;
     while (b == true) { }

tests/pos/t789.scala

@@ -1,4 +1,4 @@
-object main { // don't do this at home
+object _main { // don't do this at home
 
   trait Impl
 

tests/pos/typealiases.scala

@@ -11,7 +11,7 @@ trait Test[T] {
   def check2[S](xs: Array[S], c: Check[S]) = c(xs)
 }
 
-object main extends Test[Int] {
+object _main extends Test[Int] {
   val pair1 = (1,1)
 
   implicit def topair(x: Int): Tuple2[Int, Int] = (x,x)