RFR(S): 8154537: AArch64: some integer rotate instructions are never emitted

[Roland Westrelin]

(src >>> shift) | (src << (32 - shift)) and (src >>> shift) | (src <<
-shift) with src an int have some support in the aarch64.ad ad file:
rorI_rReg_Var_C_32 and rorI_rReg_Var_C0 but their definitions is broken
and never match any ideal graph subtree.

http://cr.openjdk.java.net/~roland/8154537/webrev.00/

Roland.