Request for reviews (L): 6761600: Use SSE 4.2 In STTNI Intrinsics

[Changpeng Fang]

Tom Rodriguez wrote:
> The string_indexOf triggering criteria in library_call.cpp seems wrong 
> since it skips the optimization for constant strings in preference for 
> the SSE4.2 version.  The constant string seems like it should be 
> preferred shouldn't it?
>
 I doubt about the constant string optimizations. I experiments on 
simple case  shows  even  though
both strings are constant, SSE4.2 version still performs better (It 
should not be the case). As a result,
constant string optimizations for indexof may not be performed as expected.

Would you please point out where is this constant optimization? Thanks,

Changpeng.