break distro out into separate files

src/distro/adoptopenjdk.ts

@@ -0,0 +1,23 @@
+import * as core from '@actions/core';
+import * as tc from '@actions/tool-cache';
+
+export async function getJavaAdoptOpenJDK(
+  version: string,
+  javaPackage: string,
+  arch: string,
+  OS: string
+) {
+  core.debug('Downloading JDK from AdoptOpenJDK');
+
+  const jdkFile = await tc.downloadTool(
+    `https://api.adoptopenjdk.net/v3/binary/latest/${normalize(
+      version
+    )}/ga/${OS}/${arch}/${javaPackage}/hotspot/normal/adoptopenjdk`
+  );
+  return [jdkFile, version];
+}
+
+function normalize(version: string): string {
+  if (version == '1.8') return '8';
+  return version;
+}