Plan for es3.d.ts

[saschanaz]

1. lib.d.ts for es3, lib.es5.full.d.ts for es5
2. fourslash baselines are for lib.d.ts, give fourslash test lib: es3 by default to suppress baseline changes as much as possible
3. support @lib setting on fourslash test to allow setting @lib: es5 for ES5-requiring tests
4. add a test to check @lib: es3 does not have ES5 types

[saschanaz]

microsoft#28372 is rejected