perf: move setting up Deno namespace to snapshot time (denoland#18067)

No need to do it on startup every time.

runtime/js/99_main.js

@@ -385,6 +385,20 @@ function promiseRejectMacrotaskCallback() {
 let hasBootstrapped = false;
 // Set up global properties shared by main and worker runtime.
 ObjectDefineProperties(globalThis, windowOrWorkerGlobalScope);
+// FIXME(bartlomieju): temporarily add whole `Deno.core` to
+// `Deno[Deno.internal]` namespace. It should be removed and only necessary
+// methods should be left there.
+ObjectAssign(internals, {
+ core,
+});
+const internalSymbol = Symbol("Deno.internal");
+const finalDenoNs = {
+ internal: internalSymbol,
+ [internalSymbol]: internals,
+ resources: core.resources,
+ close: core.close,
+ ...denoNs,
+};
 
 function bootstrapMainRuntime(runtimeOptions) {
  if (hasBootstrapped) {
@@ -452,8 +466,6 @@ function bootstrapMainRuntime(runtimeOptions) {
  setUserAgent(runtimeOptions.userAgent);
  setLanguage(runtimeOptions.locale);
 
- const internalSymbol = Symbol("Deno.internal");
-
  // These have to initialized here and not in `90_deno_ns.js` because
  // the op function that needs to be passed will be invalidated by creating
  // a snapshot
@@ -475,13 +487,6 @@ function bootstrapMainRuntime(runtimeOptions) {
  core,
  });
 
- const finalDenoNs = {
- internal: internalSymbol,
- [internalSymbol]: internals,
- resources: core.resources,
- close: core.close,
- ...denoNs,
- };
  ObjectDefineProperties(finalDenoNs, {
  pid: util.readOnly(runtimeOptions.pid),
  ppid: util.readOnly(runtimeOptions.ppid),
@@ -579,8 +584,6 @@ function bootstrapWorkerRuntime(
 
  globalThis.pollForMessages = pollForMessages;
 
- const internalSymbol = Symbol("Deno.internal");
-
  // These have to initialized here and not in `90_deno_ns.js` because
  // the op function that needs to be passed will be invalidated by creating
  // a snapshot
@@ -602,13 +605,6 @@ function bootstrapWorkerRuntime(
  core,
  });
 
- const finalDenoNs = {
- internal: internalSymbol,
- [internalSymbol]: internals,
- resources: core.resources,
- close: core.close,
- ...denoNs,
- };
  if (runtimeOptions.unstableFlag) {
  ObjectAssign(finalDenoNs, denoNsUnstable);
  // These have to initialized here and not in `90_deno_ns.js` because