Exclude import() tests from pubilsh build

I really don't like this commit, but import() is currently breaking
our publish script.
When "normal" tests we are transpiling import() so that it works
with Jest. We can't do it while publishing because we need to
publish the untranspiled import() so that it can load real .mjs files.

Follow up to #10903

Makefile

@@ -212,7 +212,7 @@ prepublish-build: clean-lib clean-runtime-helpers
 prepublish:
 	$(MAKE) bootstrap-only
 	$(MAKE) prepublish-build
-	$(MAKE) test
+	IS_PUBLISH=true $(MAKE) test
 
 new-version:
 	git pull --rebase

packages/babel-core/test/config-chain.js

@@ -1044,6 +1044,10 @@ describe("buildConfigChain", function() {
         );
         const filename = tmp("src.js");
 
+        // We can't transpile import() while publishing, and it isn't supported
+        // by jest.
+        if (process.env.IS_PUBLISH && name === "babel.config.mjs") return;
+
         await config(name);
 
         expect(await loadOptionsAsync({ filename, cwd })).toEqual({
@@ -1067,6 +1071,15 @@ describe("buildConfigChain", function() {
           `babel-test-dup-config-${name1}-${name2}`,
         );
 
+        // We can't transpile import() while publishing, and it isn't supported
+        // by jest.
+        if (
+          process.env.IS_PUBLISH &&
+          (name1 === "babel.config.mjs" || name2 === "babel.config.mjs")
+        ) {
+          return;
+        }
+
         await Promise.all([config(name1), config(name2)]);
 
         await expect(
@@ -1124,6 +1137,10 @@ describe("buildConfigChain", function() {
         );
         const filename = tmp("src.js");
 
+        // We can't transpile import() while publishing, and it isn't supported
+        // by jest.
+        if (process.env.IS_PUBLISH && name === ".babelrc.mjs") return;
+
         await config(name);
 
         expect(await loadOptionsAsync({ filename, cwd })).toEqual({
@@ -1157,6 +1174,15 @@ describe("buildConfigChain", function() {
           `babel-test-dup-config-${name1}-${name2}`,
         );
 
+        // We can't transpile import() while publishing, and it isn't supported
+        // by jest.
+        if (
+          process.env.IS_PUBLISH &&
+          (name1 === ".babelrc.mjs" || name2 === ".babelrc.mjs")
+        ) {
+          return;
+        }
+
         await Promise.all([config(name1), config(name2)]);
 
         await expect(
@@ -1187,6 +1213,10 @@ describe("buildConfigChain", function() {
       `("should show helpful errors for $config", async ({ dir, error }) => {
         const filename = fixture("config-files", dir, "src.js");
 
+        // We can't transpile import() while publishing, and it isn't supported
+        // by jest.
+        if (process.env.IS_PUBLISH && dir === "babelrc-mjs-error") return;
+
         await expect(
           loadOptionsAsync({ filename, cwd: path.dirname(filename) }),
         ).rejects.toThrow(error);