SI-9027 Backport xml parser fix

Fingers crossed, I have no local java 6 here to test.

No test because no q"" on 2.10.

Author: som-snytt

bincompat-backward.whitelist.conf

@@ -100,6 +100,12 @@ filter {
         {
             matchName="scala.reflect.runtime.SymbolLoaders.isInvalidClassName"
             problemName=MissingMethodProblem
+        },
+
+        {
+            matchName="scala.xml.dtd.ElementValidator.scala$xml$dtd$ElementValidator$$find$2"
+            problemName=IncompatibleMethTypeProblem
         }
     ]
 }
+

bincompat-forward.whitelist.conf

@@ -182,6 +182,11 @@ filter {
             # only accessible from util.parsing.combinator package
             matchName="scala.util.parsing.combinator.SubSequence"
             problemName=MissingClassProblem
+        },
+
+        {
+            matchName="scala.xml.dtd.ElementValidator.scala$xml$dtd$ElementValidator$$find$2"
+            problemName=IncompatibleMethTypeProblem
         }
     ]
 }

src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala

@@ -349,13 +349,12 @@ trait MarkupParsers {
         content_LT(ts)
 
         // parse more XML ?
-        if (charComingAfter(xSpaceOpt) == '<') {
-          xSpaceOpt
-          while (ch == '<') {
-            nextch
+        if (charComingAfter(xSpaceOpt()) == '<') {
+          do {
+            xSpaceOpt()
+            nextch()
             ts append element
-            xSpaceOpt
-          }
+          } while (charComingAfter(xSpaceOpt()) == '<')
           handle.makeXMLseq(r2p(start, start, curOffset), ts)
         }
         else {