Regression(70295) fix -- should do a sign ext after 32-bit shift in 64 bit mode
Merge branch 'regress'
Fix ProfileEntryHookStub, make sufficient space on stack for callee saved registers
Fix DSGR test-assembler-s390 testcase.  R3 and R4 needs to have full 64-bit set.
Minor improvement to RememberedSetHelper
Fix regression in ProfileEntryHookStub.

Caused by commit c80ae0b3d32e6ad5d3b34be74d60e14678a83028