Reduce stack usage for overflow checks

This reduces the stack space reserved for overflow checks to 12K, split
into an 8K gap and a 4K protected region.  GC needs over 8K when running
in a stack overflow situation.

Also prevents signal runaway by detecting a signal inside code that
resulted from a signal handler invokation.  And adds a max signal count to
the SignalTest to prevent it running forever.

Also reduces the number of iterations for the InterfaceTest as this was
taking (almost) forever with the --trace option on run-test.

Bug: 15435566

Change-Id: Id4fd46f22d52d42a9eb431ca07948673e8fda694
diff --git a/compiler/utils/stack_checks.h b/compiler/utils/stack_checks.h
index 63adbc2..ce01077 100644
--- a/compiler/utils/stack_checks.h
+++ b/compiler/utils/stack_checks.h
@@ -33,10 +33,9 @@
 // Determine whether a frame is small or large, used in the decision on whether to elide a
 // stack overflow check on method entry.
 //
-// A frame is considered large when it's either above kLargeFrameSize, or a quarter of the
-// overflow-usable stack space.
-static inline bool IsLargeFrame(size_t size, InstructionSet isa) {
-  return size >= kLargeFrameSize || size >= GetStackOverflowReservedBytes(isa) / 4;
+// A frame is considered large when it's above kLargeFrameSize.
+static inline bool FrameNeedsStackCheck(size_t size, InstructionSet isa) {
+  return size >= kLargeFrameSize;
 }
 
 }  // namespace art