Log line-at-a-time to work around Android logging lossage.

Also deduplicate the two copies of gettid, and switch image_test over
to using SignalCatcher's SIGQUIT dumping rather than rolling its own
subset.

Change-Id: I8b70aaa3a3b9258c8258728c6a66e5dc4fa6399e
diff --git a/src/runtime.cc b/src/runtime.cc
index bb3ead7..2891e56 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -399,6 +399,7 @@
   //    gDvm.numDeclaredStaticFields,
   //    gDvm.pBootLoaderAlloc->curOffset);
   // LOGI("GC precise methods: %d", dvmPointerSetGetCount(gDvm.preciseMethods));
+  os << "\n";
 }
 
 void Runtime::BlockSignals() {