Handle cc_defaults' shared for cc_library_shared

Akin to testing for cc_defaults' `static`, we introduce
a `shared` sibling to
TestStaticLibrary_SystemSharedLibsStaticEmpty

Bug: 195451854
Test: TestCcLibrarySharedSystemSharedLibsSharedEmpty
Change-Id: I63cb0641d216e8c11586ecf415fa2441e31dd3e5

bp2build/cc_library_shared_conversion_test.go

@@ -496,3 +496,27 @@ cc_library_shared {
 	},
 	)
 }
+
+func TestCcLibrarySharedSystemSharedLibsSharedEmpty(t *testing.T) {
+	runCcLibrarySharedTestCase(t, bp2buildTestCase{
+		description:                "cc_library_shared system_shared_libs empty shared default",
+		moduleTypeUnderTest:        "cc_library_shared",
+		moduleTypeUnderTestFactory: cc.LibrarySharedFactory,
+		blueprint: soongCcLibrarySharedPreamble + `
+cc_defaults {
+    name: "empty_defaults",
+    shared: {
+        system_shared_libs: [],
+    },
+    include_build_directory: false,
+}
+cc_library_shared {
+    name: "empty",
+    defaults: ["empty_defaults"],
+}
+`,
+		expectedBazelTargets: []string{makeBazelTarget("cc_library_shared", "empty", attrNameToString{
+			"system_dynamic_deps": "[]",
+		})},
+	})
+}