Revert "[arm] Use constant pool for off-heap targets"

This reverts commit cd285951.

Reason for revert: No size improvements, but 5% regression on octane/NavierStrokes:
https://chromeperf.appspot.com/report?sid=ebcd213df609b4ff31b0b25b5c8aab9d0738ff46f623161bdcdbb6f594112761&start_rev=579365&end_rev=582538

Original change's description:
> [arm] Use constant pool for off-heap targets
>
> This CL puts off-heap targets (i.e. code addresses for embedded builtins)
> in the constant pool on ARM.
>
> We are landing this CL to evaluate impact on benchmarks and code size,
> and expect to revert it once we have gathered that data.
>
> Bug: v8:6666
>
> Change-Id: If4935a6fb162cd1ffb34489c6fa9630f10ca2c9f
> Reviewed-on: https://chromium-review.googlesource.com/1154924
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54914}

TBR=sigurds@chromium.org,jgruber@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:6666, chromium:872176
Change-Id: Icd0019c7f0c890d0eb09ddc2a74745c6b68db263
Reviewed-on: https://chromium-review.googlesource.com/1172482
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55151}

src/arm/assembler-arm.cc

@@ -1097,9 +1097,6 @@ bool UseMovImmediateLoad(const Operand& x, const Assembler* assembler) {
   if (x.MustOutputRelocInfo(assembler)) {
     // Prefer constant pool if data is likely to be patched.
     return false;
-  } else if (x.IsOffHeapTarget()) {
-    // Use constant pool for off heap targets.
-    return false;
   } else {
     // Otherwise, use immediate load if movw / movt is available.
     return CpuFeatures::IsSupported(ARMv7);

src/arm/assembler-arm.h

@@ -480,7 +480,6 @@ class Operand BASE_EMBEDDED {
   Register rs() const { return rs_; }
   ShiftOp shift_op() const { return shift_op_; }
 
-  bool IsOffHeapTarget() const { return RelocInfo::IsOffHeapTarget(rmode_); }
 
  private:
   Register rm_ = no_reg;

src/arm64/macro-assembler-arm64.cc

@@ -1905,7 +1905,7 @@ void TurboAssembler::Jump(Handle<Code> code, RelocInfo::Mode rmode,
         Register scratch = temps.AcquireX();
         EmbeddedData d = EmbeddedData::FromBlob();
         Address entry = d.InstructionStartOfBuiltin(builtin_index);
-        Ldr(scratch, Operand(entry, RelocInfo::OFF_HEAP_TARGET));
+        Mov(scratch, Operand(entry, RelocInfo::OFF_HEAP_TARGET));
         Jump(scratch, cond);
         return;
       }
@@ -1963,7 +1963,7 @@ void TurboAssembler::Call(Handle<Code> code, RelocInfo::Mode rmode) {
         Register scratch = temps.AcquireX();
         EmbeddedData d = EmbeddedData::FromBlob();
         Address entry = d.InstructionStartOfBuiltin(builtin_index);
-        Ldr(scratch, Operand(entry, RelocInfo::OFF_HEAP_TARGET));
+        Mov(scratch, Operand(entry, RelocInfo::OFF_HEAP_TARGET));
         Call(scratch);
         return;
       }