[WIP] Test compiling the compiler with -Z share-generics

[Zoxc]

r? @ghost

[Zoxc]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion

[bors]

⌛ Trying commit 95bf273 with merge 02c7088d2cedc389184f692fa5318503fe12cbce...

[bors]

☀️ Try build successful - checks-azure
Build commit: 02c7088d2cedc389184f692fa5318503fe12cbce (02c7088d2cedc389184f692fa5318503fe12cbce)

[rust-timer]

Queued 02c7088d2cedc389184f692fa5318503fe12cbce with parent 8926bb4, future comparison URL.

[rust-timer]

Finished benchmarking try commit 02c7088d2cedc389184f692fa5318503fe12cbce, comparison URL.

[bjorn3]

For keccak-check clean:

Query/Function	Time	% Total Time	Δ	Full Executions	Δ	Loading	Δ
Totals	7.710	100.08%*	71.4% (3.212)	139383	0.0% (0.000)	0.000	0.0% (0.000)
typeck_tables_of	3.759	48.76%	51.0% (1.269)	3373	0.0% (0.000)	0.000	0.0% (0.000)
mir_borrowck	2.834	36.76%	105.9% (1.458)	3373	0.0% (0.000)	0.000	0.0% (0.000)
check_mod_liveness	0.301	3.90%	141.4% (0.176)	1	0.0% (0.000)	0.000	0.0% (0.000)
mir_built	0.232	3.01%	99.4% (0.116)	3373	0.0% (0.000)	0.000	0.0% (0.000)

For script-servo-check clean almost half of all queries regressed by 50% or more.

[nikomatsakis]

Closing this pull request as Zoxc is stepping back from compiler development; see rust-lang/team#316.