Add missing vcvt instructions to integrated ARM assembler.

tests_lit/assembler/arm32/vcvt.f64.s32.ll

-; Show that we know how to translate converting float to signed integer.
+; Show that we know how to translate converting signed integer to double.
 
 ; REQUIRES: allow_dump
 
 ; Compile using standalone assembler.
 ; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -Om1 \
 ; RUN:   --reg-use=s20 | FileCheck %s --check-prefix=ASM
 
 ; Show bytes in assembled standalone code.
 ; RUN: %p2i --filetype=asm -i %s --target=arm32 --assemble --disassemble \
 ; RUN:   --args -Om1 --reg-use=s20  | FileCheck %s --check-prefix=DIS
 
 ; Compile using integrated assembler.
 ; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -Om1 \
 ; RUN:   --reg-use=s20 \
 ; RUN:   | FileCheck %s --check-prefix=IASM
 
 ; Show bytes in assembled integrated code.
 ; RUN: %p2i --filetype=iasm -i %s --target=arm32 --assemble --disassemble \
 ; RUN:   --args -Om1 --reg-use=s20 | FileCheck %s --check-prefix=DIS
 
-define internal i32 @FloatToSignedInt() {
-; ASM-LABEL: FloatToSignedInt:
-; DIS-LABEL: 00000000 <FloatToSignedInt>:
-; IASM-LABEL: FloatToSignedInt:
+define internal double @SignedIntToDouble() {
+; ASM-LABEL: SignedIntToDouble:
+; DIS-LABEL: 00000000 <SignedIntToDouble>:
+; IASM-LABEL: SignedIntToDouble:
 
 entry:
-; ASM-NEXT: .LFloatToSignedInt$entry:
-; IASM-NEXT: .LFloatToSignedInt$entry:
+; ASM: .LSignedIntToDouble$entry:
+; IASM: .LSignedIntToDouble$entry:
 
-  %v = fptosi float 0.0 to i32
+  %v = sitofp i32 17 to double
 
-; ASM:  vcvt.s32.f32    s20, s20
-; DIS:   14:    eebdaaca
+; ASM:  vcvt.f64.s32    d0, s20
+; DIS:   10:   eeb80bca
 ; IASM-NOT: vcvt
 
-  ret i32 %v
+  ret double %v
 }