Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20200506' into staging

Add tcg_gen_gvec_dup_imm
Misc tcg patches

# gpg: Signature made Wed 06 May 2020 19:23:43 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20200506:
  tcg: Fix integral argument type to tcg_gen_rot[rl]i_i{32,64}
  tcg: Add load_dest parameter to GVecGen2
  tcg: Improve vector tail clearing
  tcg: Add tcg_gen_gvec_dup_tl
  tcg: Remove tcg_gen_gvec_dup{8,16,32,64}i
  tcg: Use tcg_gen_gvec_dup_imm in logical simplifications
  target/arm: Use tcg_gen_gvec_dup_imm
  target/ppc: Use tcg_gen_gvec_dup_imm
  target/s390x: Use tcg_gen_gvec_dup_imm
  tcg: Add tcg_gen_gvec_dup_imm

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>