Optimizing: Improve const-string code generation.

For strings in the boot image, use either direct pointers
or pc-relative addresses. For other strings, use PC-relative
access to the dex cache arrays for AOT and direct address of
the string's dex cache slot for JIT.

For aosp_flounder-userdebug:
  - 32-bit boot.oat: -692KiB (-0.9%)
  - 64-bit boot.oat: -948KiB (-1.1%)
  - 32-bit dalvik cache total: -900KiB (-0.9%)
  - 64-bit dalvik cache total: -3672KiB (-1.5%)
    (contains more files than the 32-bit dalvik cache)
For aosp_flounder-userdebug forced to compile PIC:
  - 32-bit boot.oat: -380KiB (-0.5%)
  - 64-bit boot.oat: -928KiB (-1.0%)
  - 32-bit dalvik cache total: -468KiB (-0.4%)
  - 64-bit dalvik cache total: -1928KiB (-0.8%)
    (contains more files than the 32-bit dalvik cache)

Bug: 26884697
Change-Id: Iec7266ce67e6fedc107be78fab2e742a8dab2696
diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 1b62531..b6b8322 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -2745,20 +2745,16 @@
 
     case Instruction::CONST_STRING: {
       uint32_t string_index = instruction.VRegB_21c();
-      bool in_dex_cache = compiler_driver_->CanAssumeStringIsPresentInDexCache(
-          *dex_file_, string_index);
       current_block_->AddInstruction(
-          new (arena_) HLoadString(graph_->GetCurrentMethod(), string_index, dex_pc, in_dex_cache));
+          new (arena_) HLoadString(graph_->GetCurrentMethod(), string_index, *dex_file_, dex_pc));
       UpdateLocal(instruction.VRegA_21c(), current_block_->GetLastInstruction(), dex_pc);
       break;
     }
 
     case Instruction::CONST_STRING_JUMBO: {
       uint32_t string_index = instruction.VRegB_31c();
-      bool in_dex_cache = compiler_driver_->CanAssumeStringIsPresentInDexCache(
-          *dex_file_, string_index);
       current_block_->AddInstruction(
-          new (arena_) HLoadString(graph_->GetCurrentMethod(), string_index, dex_pc, in_dex_cache));
+          new (arena_) HLoadString(graph_->GetCurrentMethod(), string_index, *dex_file_, dex_pc));
       UpdateLocal(instruction.VRegA_31c(), current_block_->GetLastInstruction(), dex_pc);
       break;
     }