Tests: Fix #1372: Don't legalize runtests HLSL tests.

We want these tests to be independent of whether SPIRV-opt is used.
diff --git a/Test/runtests b/Test/runtests
index 51e15c0..a084cb5 100755
--- a/Test/runtests
+++ b/Test/runtests
@@ -77,11 +77,11 @@
 # Testing -S and compound suffixes
 #
 echo Running explicit stage test and compound suffix tests
-$EXE -i -S vert nosuffix > $TARGETDIR/nosuffix.out
+$EXE -Od -i -S vert nosuffix > $TARGETDIR/nosuffix.out
 diff -b $BASEDIR/nosuffix.out $TARGETDIR/nosuffix.out || HASERROR=1
-$EXE -i compoundsuffix.vert.glsl > $TARGETDIR/compoundsuffix.vert.glsl
+$EXE -Od -i compoundsuffix.vert.glsl > $TARGETDIR/compoundsuffix.vert.glsl
 diff -b $BASEDIR/compoundsuffix.vert.glsl $TARGETDIR/compoundsuffix.vert.glsl || HASERROR=1
-$EXE -e main -H compoundsuffix.frag.hlsl > $TARGETDIR/compoundsuffix.frag.hlsl
+$EXE -Od -e main -H compoundsuffix.frag.hlsl > $TARGETDIR/compoundsuffix.frag.hlsl
 diff -b $BASEDIR/compoundsuffix.frag.hlsl $TARGETDIR/compoundsuffix.frag.hlsl || HASERROR=1
 
 #