Avoid cross-platform preprocessor need from test

The test requires 32-bit, but does not need preprocessing. So avoid any
attempt to invoke a platform-specific preprocessor (that might not
actually be available).

Author: tautschnig

regression/cbmc/Anonymous_Struct3/main.c renamed to regression/cbmc/Anonymous_Struct3/main.i

@@ -1,5 +1,5 @@
 CORE
-main.c
+main.i
 -win32
 ^EXIT=0$
 ^SIGNAL=0$

regression/cbmc/Anonymous_Struct3/test.desc

@@ -1,5 +1,5 @@
 CORE
-main.c
+main.i
 -winx64
 ^EXIT=0$
 ^SIGNAL=0$

regression/cbmc/noop1/main.c renamed to regression/cbmc/noop1/main.i

@@ -1,5 +1,5 @@
 CORE
-main.c
+main.i
 -win32
 ^EXIT=0$
 ^SIGNAL=0$