In JSDocs notation for index signatures, Object and object should be treated as the same

TypeScript Version: 2.7.0-dev.201xxxxx

Code

/**
 * Test.
 *
 * @param {object.<string, number>} obj An object.
 */
function func(obj) {
	console.log(obj);
}

Expected behavior:

obj should have a index signature as in #15105

Actual behavior:

obj is treated as any

Additional Info:

This was mentioned in the above issue, and it seems to be related to the way Typescript manage Object and object, but in JSDocs, they are treated similar.

Start by reproducing the provided JSDoc example with the TypeScript version under investigation and compare it with the behavior described in issue #15105. Trace how the JSDoc index-signature annotation is interpreted, then verify that object.<string, number> gives obj an index signature instead of any.