tsc does not use amd-module name when emitting dynamic imports

TypeScript Version: 3.3.0-dev.20190118

Search Terms: amd-module, optional, dynamic, directive

Code

Scripts/foo.ts

///<amd-module name="customNameFoo" />

export function hello() {
    console.log('hello world');
}

Scripts/bar.ts

///<amd-module name="customNameBar" />

async function myFunction(): Promise<void> {
	//Dynamically import foo
        var fooModule = await import('./foo');

	fooModule.hello();
}

tsconfig.json

{
	"compileOnSave": true,
	"compilerOptions": {
		"target": "es5",
		"outDir": "GeneratedScripts",
		"module": "amd",
		"lib": [
			"es2015.promise",
			"dom",
			"es5",
			"scripthost"
		]
	},
	"include": [
		"Scripts/**/*"
	],
	"exclude": [
		"GeneratedScripts"
	]
}

would expect that the call to require would use the amd-module name for foo ("customNameFoo") and not "./foo". (If we non-dynamically imported foo, then the generated 'define' would refer to foo by it's amd-module name)
GeneratedScripts/bar.js

//...

return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, new Promise(function (resolve_1, reject_1) { require(['./foo'], resolve_1, reject_1); })];
                    case 1:
                        fooModule = _a.sent();
                        fooModule.hello();
                        return [2 /*return*/];
                }
            });

Expected behavior: The generated amd code for a dynamic import should use the name of the module specified in the amd-module directive

Actual behavior: The generated code for the dynamic import uses relative path to the module

Related Issues:
https://github.com/Microsoft/TypeScript/pull/1158
https://github.com/Microsoft/TypeScript/issues/28760

Reproduce the issue with Scripts/foo.ts, Scripts/bar.ts, and tsconfig.json, then inspect the compiler entry point for AMD dynamic-import emission. Compare GeneratedScripts/bar.js with the expected output; done means the generated require call uses foo's customNameFoo AMD module name instead of './foo'.