revert 9dcb0815f970 - LDFLAGS should not define -shared (issue 3576)

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branch : release-pypy3.8-v7.x
2 jobs for release-pypy3.8-v7.3.6 in 28 minutes and 47 seconds
latest
Status Name Job ID Coverage
  Test
passed check_rpython_annotations #254247

00:07:31

passed hpy_tests #254248

00:28:47