Subzero, MIPS32: Remove --skip-unimplemented from lit tests

tests_lit/llvm2ice_tests/return_immediates.ll

 ; Simple test that returns various immediates. For fixed-width instruction
 ; sets, some immediates are more complicated than others.
 ; For x86-32, it shouldn't be a problem.
 
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -O2 \
 ; RUN:      -allow-externally-defined-symbols | FileCheck %s
 
 ; RUN: %if --need=target_ARM32 \
 ; RUN:   --command %p2i --filetype=obj \
 ; RUN:   --disassemble --target arm32 -i %s --args -O2 \
 ; RUN:   | %if --need=target_ARM32 \
 ; RUN:   --command FileCheck --check-prefix ARM32 %s
 
 ; TODO(rkotler): Stop skipping unimplemented parts (via --skip-unimplemented)
 ; once enough infrastructure is in. Also, switch to --filetype=obj
 ; when possible.
 ; RUN: %if --need=target_MIPS32 --need=allow_dump \
 ; RUN:   --command %p2i --filetype=asm --assemble \
-; RUN:   --disassemble --target mips32 -i %s --args -O2 --skip-unimplemented \
+; RUN:   --disassemble --target mips32 -i %s --args -O2 \
 ; RUN:   | %if --need=target_MIPS32 --need=allow_dump \
 ; RUN:   --command FileCheck --check-prefix MIPS32 %s
 
 ; Test 8-bits of all ones rotated right by various amounts (even vs odd).
 ; ARM has a shifter that allows encoding 8-bits rotated right by even amounts.
 ; The first few "rotate right" test cases are expressed as shift-left.
 
 define internal i32 @ret_8bits_shift_left0() {
   ret i32 255
 }
@@ skipping 287 matching lines @@
 ; CHECK-LABEL: ret_addr
 ; CHECK-NEXT: mov eax,0x0 {{.*}} R_386_32 _start
 ; ARM32-LABEL: ret_addr
 ; ARM32-NEXT: movw r0, #0 {{.*}} R_ARM_MOVW_ABS_NC _start
 ; ARM32-NEXT: movt r0, #0 {{.*}} R_ARM_MOVT_ABS    _start
 ; TODO(RKotler) emitting proper li but in disassembly
 ; it shows up only in the relocation records. Should emit
 ; without the macro but we still need to add GOT implementation
 ; to finish this case
 ;