[SR-9461] Duplicated output in `swift build` progress

[neonichu]

Previous ID	SR-9461
Radar	rdar://problem/46581873
Original Reporter	@neonichu
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Package Manager
Labels	Bug
Assignee	None
Priority	Medium

md5: d7ad361b87e8b97bb0d57c870b87955d

Issue Description:

Looks like #1876 might have introduced a regression.

For example, when looking at the output for https://github.com/jpsim/Yams:

$ swift build > build.log
$ cat build.log
[1/9] Compiling CYaml src/reader.c
[2/9] Compiling CYaml src/scanner.c
[3/9] Compiling CYaml src/parser.c
[4/9] Compiling CYaml src/writer.c
[5/9] Compiling CYaml src/emitter.c
[6/9] Compiling CYaml src/api.c
[7/9] Compiling CYaml src/api.c
[8/9] Compile Swift Module 'Yams' (16 sources)
[9/9] Compile Swift Module 'Yams' (16 sources)

The "Compile Swift Module" line is duplicated.

[aciidgh]

#1913