fix #128085 - SIGSEGV in S_regmatch with S_study_chunk: Assertion "!frame" failed.

The goto target should have been before the if (frame) block.

Clearly this code is not well tested in our test suite. This patch
does NOT include tests.

Author: demerphq

regcomp.c

@@ -5899,15 +5899,10 @@ Perl_re_printf( aTHX_  "LHS=%"UVuf" RHS=%"UVuf"\n",
 	/* Else: zero-length, ignore. */
 	scan = regnext(scan);
     }
-    /* If we are exiting a recursion we can unset its recursed bit
-     * and allow ourselves to enter it again - no danger of an
-     * infinite loop there.
-    if (stopparen > -1 && recursed) {
-	DEBUG_STUDYDATA("unset:", data,depth);
-        PAREN_UNSET( recursed, stopparen);
-    }
-    */
+
+  finish:
     if (frame) {
+        /* we need to unwind recursion. */
         depth = depth - 1;
 
         DEBUG_STUDYDATA("frame-end:",data,depth);
@@ -5924,7 +5919,6 @@ Perl_re_printf( aTHX_  "LHS=%"UVuf" RHS=%"UVuf"\n",
         goto fake_study_recurse;
     }
 
-  finish:
     assert(!frame);
     DEBUG_STUDYDATA("pre-fin:",data,depth);