Request for reviews (XS): 7123926: Some CTW test crash: !_control.contains(ctrl)

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/7123926/webrev

7123926: Some CTW test crash: !_control.contains(ctrl)

Don't try to eliminate Integer::toString() call node during String concatenation 
optimization if it's result has several uses.

Eliminate case:
   foo (Integer intob) {
     String str = "int: " + intobj;

Keep case:
   foo (Integer intob) {
     String intstr = intobj.toString();
     String str = "int: " + intobj; // second use is in SB allocation debug info

Tested with failed test.

Thanks,
Vladimir