[11u] RFR 8253923: C2 doesn't always run loop opts for compilations that include loops

[Roland Westrelin]

Original bug:
  https://bugs.openjdk.java.net/browse/JDK-8253923
  https://github.com/openjdk/jdk/commit/a6c23b77
 
Original patch does not apply cleanly to 11u because code around a
couple changes is different. Patch is otherwise identical. See below for
hunks that failed to apply.
 
11u webrev:
  https://cr.openjdk.java.net/~roland/8253923.11u/webrev.00/
 
Testing: x86_64 build, tier1, some complile the world testing

Roland.

--- callGenerator.cpp
+++ callGenerator.cpp
@@ -456,7 +456,6 @@ void LateInlineCallGenerator::do_late_inline() {
       result = (result_size == 1) ? kit.pop() : kit.pop_pair();
     }
 
-    C->set_has_loops(C->has_loops() || _inline_cg->method()->has_loops());
     C->env()->notice_inlined_method(_inline_cg->method());
     C->set_inlining_progress(true);
     C->set_do_cleanup(kit.stopped()); // path is dead; needs cleanup

--- compile.cpp
+++ compile.cpp
@@ -1022,6 +1022,7 @@ void Compile::Init(int aliaslevel) {
 #ifdef ASSERT
   _type_verify_symmetry = true;
   _phase_optimize_finished = false;
+  _exception_backedge = false;
 #endif
 }