Refactor snapshot build (#2825)

Instead of using core/snapshot_creator.rs, instead two crates are
introduced which allow building the snapshot during build.rs.

Rollup is removed and replaced with our own bundler. This removes
the Node build dependency. Modules in //js now use Deno-style imports
with file extensions, rather than Node style extensionless imports.

This improves incremental build time when changes are made to //js files
by about 40 seconds.

1 files changed, 4 insertions, 7 deletions

diff --git a/js/error_stack_test.ts b/js/error_stack_test.ts
index 0df491f39..4c7edb2fd 100644
--- a/js/error_stack_test.ts
+++ b/js/error_stack_test.ts
@@ -90,22 +90,19 @@ test(function prepareStackTrace(): void {
     structuredStackTrace: CallSite[]
   ) => string = MockError.prepareStackTrace;
   const result = prepareStackTrace(new Error("foo"), [
-    getMockCallSite("gen/cli/bundle/main.js", 23, 0)
+    getMockCallSite("CLI_SNAPSHOT.js", 23, 0)
   ]);
   assert(result.startsWith("Error: foo\n"));
-  assert(
-    result.includes("<anonymous> (js/"),
-    "should remap to something in 'js/'"
-  );
+  assert(result.includes(".ts:"), "should remap to something in 'js/'");
 });
 
 test(function applySourceMap(): void {
   const result = Deno.applySourceMap({
-    filename: "gen/cli/bundle/main.js",
+    filename: "CLI_SNAPSHOT.js",
     line: 23,
     column: 0
   });
-  assert(result.filename.startsWith("js/"));
+  assert(result.filename.endsWith(".ts"));
   assert(result.line != null);
   assert(result.column != null);
 });