Fix bitcode parser to check type signatures of functions.

tests_lit/llvm2ice_tests/div_legalization.ll

 ; This is a regression test that idiv and div operands are legalized
 ; (they cannot be constants and can only be reg/mem for x86).
 
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -O2 | FileCheck %s
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -Om1 | FileCheck %s
 
-define internal i32 @Sdiv_const8_b(i8 %a) {
+define internal i32 @Sdiv_const8_b(i32 %a32) {
 ; CHECK-LABEL: Sdiv_const8_b
 entry:
+  %a = trunc i32 %a32 to i8
   %div = sdiv i8 %a, 12
 ; CHECK: mov {{.*}},0xc
 ; CHECK-NOT: idiv 0xc
   %div_ext = sext i8 %div to i32
   ret i32 %div_ext
 }
 
-define internal i32 @Sdiv_const16_b(i16 %a) {
+define internal i32 @Sdiv_const16_b(i32 %a32) {
 ; CHECK-LABEL: Sdiv_const16_b
 entry:
+  %a = trunc i32 %a32 to i16
   %div = sdiv i16 %a, 1234
 ; CHECK: mov {{.*}},0x4d2
 ; CHECK-NOT: idiv 0x4d2
   %div_ext = sext i16 %div to i32
   ret i32 %div_ext
 }
 
 define internal i32 @Sdiv_const32_b(i32 %a) {
 ; CHECK-LABEL: Sdiv_const32_b
 entry:
@@ skipping 22 matching lines @@
 }
 
 define internal i32 @Urem_const_b(i32 %a) {
 ; CHECK-LABEL: Urem_const_b
 entry:
   %rem = urem i32 %a, 4567
 ; CHECK: mov {{.*}},0x11d7
 ; CHECK-NOT: div 0x11d7
   ret i32 %rem
 }