8233364: Fix undefined behavior in Canonicalizer::do_ShiftOp
Summary: Add java_shift_xxx helpers and use them.
Reviewed-by: aph, kvn
/build/
/dist/
/.idea/
nbproject/private/
/webrev
/.src-rev
/.jib/
.DS_Store
.metadata/
.recommenders/
test/nashorn/script/external
test/nashorn/lib
NashornProfile.txt
**/JTreport/**
**/JTwork/**