PP: Fix #1694: Handle badly formed argument substitution.

Also added a warning for no space after a macro name.
diff --git a/gtests/AST.FromFile.cpp b/gtests/AST.FromFile.cpp
index 8755246..2f1f011 100644
--- a/gtests/AST.FromFile.cpp
+++ b/gtests/AST.FromFile.cpp
@@ -96,6 +96,7 @@
         "cppNest.vert",
         "cppBad.vert",
         "cppBad2.vert",
+        "cppBad3.vert",
         "cppComplexExpr.vert",
         "cppDeepNest.frag",
         "cppPassMacroName.frag",