Always respect system_shared_libs from Android.bp

This commit removes a special case that ignores `system_shared_libs`
when `sdk_version`, `vendor_available`, or `vendor` is specified.

In the past, that special case was required for `libasync_safe` and
`libpropertyinfoparser`.  However, ignoring `system_shared_libs` meant
that we didn't have a way to skip the default libs when `sdk_version`
was specified.  This becomes a problem when the dependencies of
prebuilts are actually checked.  To be specific,
`libclang_rt.builtins-${arch}` falls into circular dependencies.

Bug: 123006819
Test: make checkbuild
Change-Id: I5fe038c00892b3abe5189b30d57ba59884b47cbb

cc/linker.go

@@ -240,11 +240,11 @@ func (linker *baseLinker) linkerDeps(ctx DepsContext, deps Deps) Deps {
 			deps.LateStaticLibs = append(deps.LateStaticLibs, "libgcc")
 		}
 
-		var systemSharedLibs []string
-		if !ctx.useSdk() && !ctx.useVndk() {
-			systemSharedLibs = linker.Properties.System_shared_libs
-		}
+		systemSharedLibs := linker.Properties.System_shared_libs
 		if systemSharedLibs == nil {
+			// Provide a default system_shared_libs if it is unspecified. Note: If an
+			// empty list [] is specified, it implies that the module declines the
+			// default system_shared_libs.
 			systemSharedLibs = []string{"libc", "libm", "libdl"}
 		}