hg: jdk8u/jdk8u-dev/hotspot: 8198304: VS2017 (C4838, C4312) Various conversion issues with gtest tests

[kevin.walls at oracle.com]

Changeset: 0fa4c2b668b9
Author:    kevinw
Date:      2018-06-22 01:55 -0700
URL:       http://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot/rev/0fa4c2b668b9

8198304: VS2017 (C4838, C4312) Various conversion issues with gtest tests
Summary: Introduce specific casts to fix multiple type cast conversion compilation errors.
Reviewed-by: coffeys, lfoltan, gtriantafill, hseigel

! src/share/vm/memory/guardedMemory.cpp