* Remove indirect-load for constants on Xtensa Target to improve performance
* Remove const intrinsics flags for xtensa instead of adding too much #ifdef
* Add AOT_INTRINSIC_FLAG_F32_CONST for xtensa frontend, because espressif xtensa llvm backend does not support float-point immediate for now
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Co-authored-by: zhanheng1 <Zhanheng.Qin@sony.com>