Respect @inline decorator in LLVM backend

[czgdp1807]

https://github.com/lcompilers/lpython/pull/1057/files#r957303054

Command - lpython --show-llvm integration_tests/expr_01.py

; ModuleID = 'LFortran'
source_filename = "LFortran"

@0 = private unnamed_addr constant [16 x i8] c"AssertionError\0A\00", align 1
@1 = private unnamed_addr constant [16 x i8] c"AssertionError\0A\00", align 1
@2 = private unnamed_addr constant [16 x i8] c"AssertionError\0A\00", align 1

define void @_lpython_main_program() {
.entry:
  call void @main0()
  br label %return

return:                                           ; preds = %.entry
  ret void
}

define void @main0() {
.entry:
  %_lpython_return_variable_add = alloca i32, align 4
  %_lpython_return_variable_and_op = alloca i32, align 4
  %x = alloca i32, align 4
  %x_add = alloca i32, align 4
  %x_and_op = alloca i32, align 4
  %y = alloca i32, align 4
  %y_add = alloca i32, align 4
  %y_and_op = alloca i32, align 4
  %z = alloca i32, align 4
  store i32 25, i32* %x, align 4
  %0 = load i32, i32* %x, align 4
  store i32 %0, i32* %x_add, align 4
  store i32 2, i32* %y_add, align 4
  %1 = load i32, i32* %x_add, align 4
  %2 = load i32, i32* %y_add, align 4
  %3 = add i32 %1, %2
  store i32 %3, i32* %_lpython_return_variable_add, align 4
  br label %goto_target

unreachable_after_goto:                           ; No predecessors!
  br label %goto_target

goto_target:                                      ; preds = %unreachable_after_goto, %.entry
  %4 = load i32, i32* %_lpython_return_variable_add, align 4
  %5 = mul i32 %4, 2
  store i32 %5, i32* %y, align 4
  %6 = load i32, i32* %x, align 4
  %7 = icmp eq i32 %6, 25
  br i1 %7, label %then, label %else

then:                                             ; preds = %goto_target
  br label %ifcont

else:                                             ; preds = %goto_target
  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @0, i32 0, i32 0))
  call void @exit(i32 1)
  br label %ifcont

ifcont:                                           ; preds = %else, %then
  %8 = load i32, i32* %y, align 4
  %9 = icmp eq i32 %8, 54
  br i1 %9, label %then1, label %else2

then1:                                            ; preds = %ifcont
  br label %ifcont3

else2:                                            ; preds = %ifcont
  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @1, i32 0, i32 0))
  call void @exit(i32 1)
  br label %ifcont3

ifcont3:                                          ; preds = %else2, %then1
  %10 = load i32, i32* %x, align 4
  store i32 %10, i32* %x_and_op, align 4
  %11 = load i32, i32* %y, align 4
  store i32 %11, i32* %y_and_op, align 4
  %12 = load i32, i32* %x_and_op, align 4
  %13 = load i32, i32* %y_and_op, align 4
  %14 = and i32 %12, %13
  store i32 %14, i32* %_lpython_return_variable_and_op, align 4
  br label %goto_target5

unreachable_after_goto4:                          ; No predecessors!
  br label %goto_target5

goto_target5:                                     ; preds = %unreachable_after_goto4, %ifcont3
  %15 = load i32, i32* %_lpython_return_variable_and_op, align 4
  store i32 %15, i32* %z, align 4
  %16 = load i32, i32* %z, align 4
  %17 = icmp eq i32 %16, 16
  br i1 %17, label %then6, label %else7

then6:                                            ; preds = %goto_target5
  br label %ifcont8

else7:                                            ; preds = %goto_target5
  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @2, i32 0, i32 0))
  call void @exit(i32 1)
  br label %ifcont8

ifcont8:                                          ; preds = %else7, %then6
  br label %return

return:                                           ; preds = %ifcont8
  ret void
}

declare void @_lfortran_printf(i8*, ...)

declare void @exit(i32)

define i32 @main() {
.entry:
  call void @_lpython_main_program()
  ret i32 0
}

[certik]

I think that's fine, thanks!