Don't call toSourceString on every single method that we convert

This will save a bunch of memory until we write out the dex (we use the toSourceString for sorting)
Currently this will add the string representation (cached) to all methods when we process them

Change-Id: Iaa653e7d0e22712437ab3f112476e99e5ea6a0b2
diff --git a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
index dbdc2dc..4128265 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
@@ -1620,7 +1620,8 @@
       code.print(printer);
       printer.end("cfg");
     }
-    if (options.extensiveLoggingFilter.contains(code.method.method.toSourceString())) {
+    if (options.extensiveLoggingFilter.size() > 0
+        && options.extensiveLoggingFilter.contains(code.method.method.toSourceString())) {
       String current = code.toString();
       System.out.println();
       System.out.println("-----------------------------------------------------------------------");