[backport] SI-7710 fix memory performance of RegexParsers in jdk7u6+

Backport of scala/scala-parser-combinators@91584dc.

---

Starting with 1.7.0_06 [1], String.substring no longer reuses the internal
char array of the String but make a copy instead. Since we call
subSequence twice for *every* input character, this results in horrible
parse performance and GC.

With the benchmark from the (duplicate) ticket SI-8542, I get:

BEFORE:
    parseAll(new StringReader(String))
    For 100 items: 49 ms
    For 500 items: 97 ms
    For 1000 items: 155 ms
    For 5000 items: 113 ms
    For 10000 items: 188 ms
    For 50000 items: 1437 ms
    ===
    parseAll(String)
    For 100 items: 4 ms
    For 500 items: 67 ms
    For 1000 items: 372 ms
    For 5000 items: 5693 ms
    For 10000 items: 23126 ms
    For 50000 items: 657665 ms

AFTER:
    parseAll(new StringReader(String))
    For 100 items: 43 ms
    For 500 items: 118 ms
    For 1000 items: 217 ms
    For 5000 items: 192 ms
    For 10000 items: 196 ms
    For 50000 items: 1424 ms
    ===
    parseAll(String)
    For 100 items: 2 ms
    For 500 items: 8 ms
    For 1000 items: 16 ms
    For 5000 items: 79 ms
    For 10000 items: 161 ms
    For 50000 items: 636 ms

[1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6924259

1 files changed, 5 insertions, 1 deletions

diff --git a/bincompat-forward.whitelist.conf b/bincompat-forward.whitelist.conf
index 7879ecfd84..d8a91f3ae8 100644
--- a/bincompat-forward.whitelist.conf
+++ b/bincompat-forward.whitelist.conf
@@ -177,7 +177,11 @@ filter {
         {
             matchName="scala.reflect.runtime.JavaMirrors#JavaMirror.scala$reflect$runtime$JavaMirrors$JavaMirror$$followStatic"
             problemName=MissingMethodProblem
+        },
+        {
+            # only accessible from util.parsing.combinator package
+            matchName="scala.util.parsing.combinator.SubSequence"
+            problemName=MissingClassProblem
         }
-
     ]
 }