Fix non power-of-two Storable.alignment in Capi_Ctype tests

Alignments passed to alloca and friends must be a power of two for the code
in allocatePinned to work properly. Commit 41230e26 ("Zero out pinned
block alignment slop when profiling") introduced an ASSERT for this but
this test was still violating it.

testsuite/tests/ffi/should_run/Capi_Ctype_001.hsc

@@ -35,7 +35,7 @@ foreign import capi unsafe "capi_ctype_001.h g"
 
 instance Storable Foo where
     sizeOf _ = #size Foo
-    alignment = sizeOf
+    alignment _ = #alignment Foo
     peek p = do i <- (# peek Foo, i) p
                 j <- (# peek Foo, j) p
                 k <- (# peek Foo, k) p

testsuite/tests/ffi/should_run/Capi_Ctype_A_001.hsc

@@ -16,7 +16,7 @@ data FooA = FooA {
 
 instance Storable FooA where
     sizeOf _ = #size Foo
-    alignment = sizeOf
+    alignment _ = #alignment Foo
     peek p = do i <- (# peek Foo, i) p
                 j <- (# peek Foo, j) p
                 k <- (# peek Foo, k) p

testsuite/tests/ffi/should_run/Capi_Ctype_A_002.hsc

@@ -17,7 +17,7 @@ data {-# CTYPE "capi_ctype_002_A.h" "Foo" #-}
 
 instance Storable Foo where
     sizeOf _ = #size Foo
-    alignment = sizeOf
+    alignment _ = #alignment Foo
     peek p = do i <- (# peek Foo, i) p
                 j <- (# peek Foo, j) p
                 k <- (# peek Foo, k) p