test(core): fix schematics calls to run synchronously (#34364)

Previously the calls to run the schematics were not being properly
or consistently awaited in the tests. While this currently does not
affect the tests' performance, this fix corrects the syntax and
adds stability for future changes.

PR Close #34364

packages/core/schematics/utils/typescript/compiler_host.ts

@@ -22,7 +22,7 @@ export function createMigrationCompilerHost(
     const treeRelativePath = relative(basePath, fileName);
     const fakeOutput = fakeRead ? fakeRead(treeRelativePath) : null;
     const buffer = fakeOutput === null ? tree.read(treeRelativePath) : fakeOutput;
-    // Strip BOM as otherwise TSC methods (Ex: getWidth) will return an offset which
+    // Strip BOM as otherwise TSC methods (Ex: getWidth) will return an offset,
     // which breaks the CLI UpdateRecorder.
     // See: https://github.com/angular/angular/pull/30719
     return buffer ? buffer.toString().replace(/^\uFEFF/, '') : undefined;