only use expanded short-circuiting conditionals for expressions with
potential side-effects.

Conservatively assume aggreate and selection operators have side effects for now.

BUG=
ANGLEBUG=486
R=geofflang@chromium.org, kbr@chromium.org, nicolas@transgaming.com, shannonwoods@chromium.org

Review URL: https://codereview.appspot.com/14441075

Conflicts:
	src/common/version.h
	src/compiler/translator.vcxproj
	src/compiler/translator.vcxproj.filters
	src/compiler/translator/OutputHLSL.cpp
	src/libGLESv2/ProgramBinary.cpp
	src/libGLESv2/Shader.cpp
	src/libGLESv2/Shader.h

Change-Id: Iaf9f10b5de7b33c927ef032f3c4fe9d5095f64dd