[m-rev.] diff: fix failing invalid tests

[Julien Fischer]

Hi,

Zoltan, I'm assuming that this wasn't intended.

------------------------------

Fix failing invalid tests.

Commit ef290a0 broke two of the invalid tests: merge_inst_error and multimode_dcg.

compiler/mode_errors.m:
     Revert the part of the commit that broke the tests.

Julien.

diff --git a/compiler/mode_errors.m b/compiler/mode_errors.m
index 798e39a..e6dbc34 100644
--- a/compiler/mode_errors.m
+++ b/compiler/mode_errors.m
@@ -630,8 +630,7 @@ context_inst_to_pieces(ModeInfo, InclFileName, Context - Inst) = Pieces :-
          InclFileName = yes,
          ContextStr = FileName ++ ":" ++ LineNumStr ++ ":"
      ),
-    Pieces = [fixed(ContextStr), nl,
-        words(inst_to_string(ModeInfo, Inst)), nl].
+    Pieces = [fixed(ContextStr), words(inst_to_string(ModeInfo, Inst)), nl].

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