Fixes ARM32 VFP calling convetion.

Packs VFP arguments as tight as the ABI wants, and adds tests for
float and double arguments. vector argument tests will come soon.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4076
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/1348393002 .

tests_lit/llvm2ice_tests/phi_invalid.test

diff --git a/tests_lit/llvm2ice_tests/phi_invalid.test b/tests_lit/llvm2ice_tests/phi_invalid.test
index 198de4c..184f08c 100644
--- a/tests_lit/llvm2ice_tests/phi_invalid.test
+++ b/tests_lit/llvm2ice_tests/phi_invalid.test
@@ -2,6 +2,7 @@
 ; https://code.google.com/p/nativeclient/issues/detail?id=4304
 
 RUN: %p2i --expect-fail --tbc -i %p/Input/phi-invalid.tbc --insts 2>&1 \
+RUN:        --filetype=obj --args -o /dev/null \
 RUN:        | FileCheck --check-prefix=BADPHI %s
 
 ; BADPHI: Phi error: