Split the core/platform API into stable and legacy versions.

For now, everything outside libcore still uses the legacy version.

Test: treehugger
Bug: 157640067
Change-Id: If5234e9ee533ff537926801a0af045d36b1caf01
diff --git a/java/sdk_test.go b/java/sdk_test.go
index 52d2df5..e5d322c 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -156,9 +156,9 @@
 		{
 
 			name:           "nostdlib system_modules",
-			properties:     `sdk_version: "none", system_modules: "core-platform-api-stubs-system-modules"`,
-			system:         "core-platform-api-stubs-system-modules",
-			bootclasspath:  []string{"core-platform-api-stubs-system-modules-lib"},
+			properties:     `sdk_version: "none", system_modules: "legacy-core-platform-api-stubs-system-modules"`,
+			system:         "legacy-core-platform-api-stubs-system-modules",
+			bootclasspath:  []string{"legacy-core-platform-api-stubs-system-modules-lib"},
 			java8classpath: []string{},
 		},
 		{