build: enable code splitting for esbuild bundling of compiler-cli (#43932)

Enables code spitting for ESBuild bundling of the compiler-cli. When
we initially configured ESBuild as part of APF v13, we left this option
disabled as code splitting is marked experimental. The ESM splitting
mechanism in ESBuild seems very solid so far (judging subjectively
and by experience/reports in the ESBuild repo), so we should give
it a shot, in order to significantly reduce the size of the NPM package,
and simplify debugging (by not having duplicated code portions for all
the different entry points).

To clarify: Code splitting is helpful as we have multiple entry-points
that currently duplicate code. With code splitting these entry-points
would share common code instead.

PR Close #43932

packages/compiler-cli/BUILD.bazel

@@ -58,6 +58,7 @@ esbuild(
     ],
     format = "esm",
     platform = "node",
+    splitting = True,
     target = "node12",
     deps = PUBLIC_TARGETS,
 )