[Emit] Some import statements not emitted

[mhegazy]

In tests/cases/compiler/privacyTopLevelInternalReferenceImportWithExport.ts:

Everything declaration of the form:

im_public__private

or

im_public__public

is not emitted.

In tests/cases/compiler/privacyTopLevelInternalReferenceImportWithoutExport.ts:

Everything declaration of the form:

im_private__private

or

im_private__public

is not emitted.

For both cases, used to emit:

var im_private_c_public = m_public . c_public ;

and the like

[ahejlsberg]

The only difference I see is that the new compiler doesn't generate an (otherwise unused) local variable for an exported import statement. Specifically, given:

export import a = b;

the old compiler would generate:

var a = b;
exports.a = a;

where the new compiler simply generates:

exports.a = b;

Both compilers rewrite all references to a into exports.a so the new scheme definitely seems better.