Add a new action, LoadModuleJobAction, that the driver can use to schedule a
load of a given module before we fan out and invoke the frontend multiple
times. This gives the module interface loader a chance to compile it from a
module interface before we start with parallel invocations, avoiding starting
potentially dozens of redundant compiles of a large module. Start by using this
on the standard library.
Quick fix for rdar://52839445
* E101: indentation contains mixed spaces and tabs
* E111: indentation is not a multiple of four
* E128: continuation line under-indented for visual indent
* E302: expected 2 blank lines, found 1
* W191: indentation contains tabs
This is only the driver side of the work; the frontend doesn't understand
this new -output-filelist option yet. Next commit.
More https://bugs.swift.org/browse/SR-280.
