What this PR does / why we need it:
将openGauss 适配到x86平台的openEuler环境下，修改此处get_PlatForm_str.sh脚本，使得在x86平台的openEuler环境下编译三方库源码时能够获取到该平台信息。
Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

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