RFR: JDK-8280274: Guard printing code of Compile::print_method in PRODUCT

[Tobias Holenstein]

In `Compile::print_method(CompilerPhaseType cpt, Node* n, int level)` the code 
``` 
ResourceMark rm; 
stringStream ss; 
ss.print_raw(CompilerPhaseTypeHelper::to_string(cpt)); 
if (n != NULL) { 
  ss.print(": %d %s ", n->_idx, NodeClassNames[n->Opcode()]); 
} else { 
  ss.print_raw(": NULL"); 
} 
``` 
should to be guarded by a `#ifndef PRODUCT` since the usage of the string is also guarded in `Compile::print_method_impl`

Tested on Tier1-3

-------------

Commit messages:
 - JDK-8280274: Guard printing code of Compile::print_method in PRODUCT

Changes: https://git.openjdk.java.net/jdk/pull/7158/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7158&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280274
  Stats: 8 lines in 2 files changed: 2 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7158.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7158/head:pull/7158

PR: https://git.openjdk.java.net/jdk/pull/7158