AstTypeStubPaths* tests produce different analysis results

[AlexanderSher]

Following #90. During different test runs, produced ModuleAnalysis may contain different values for child modules.

[MikhailArkhipov]

Actually, many tests that handle references pass on re-run. Most probably b/c there is no sync point on module import completion.

[MikhailArkhipov]

Incorrect setting of analysis (old version wins) due to threading issues.