7128532: G1: Change default value of G1DefaultMaxNewGenPercent to 80

Reviewed-by: tonyp, jmasa
diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp
index 5e3da5a..d126458 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp
@@ -295,7 +295,7 @@
           "Percentage (0-100) of the heap size to use as minimum "          \
           "young gen size.")                                                \
                                                                             \
-  develop(uintx, G1DefaultMaxNewGenPercent, 50,                             \
+  develop(uintx, G1DefaultMaxNewGenPercent, 80,                             \
           "Percentage (0-100) of the heap size to use as maximum "          \
           "young gen size.")