[Native] Drop explicit -fPIC flag setup

We don't need to explicitly set -fPIC flag everywhere
because since d82109cc92
it is set by default for all ClangArgs users.

kotlin-native/llvmCoverageMappingC/build.gradle.kts

@@ -45,9 +45,6 @@ native {
             cxxflags += "-DKONAN_MACOS=1"
         }
     }
-    if (!HostManager.hostIsMingw) {
-        cxxflags += "-fPIC"
-    }
     suffixes {
         (".cpp" to ".$obj") {
             tool(*platformManager.hostPlatform.clang.clangCXX("").toTypedArray())