Revert "[vm] Fix clobbered THR/R14 in StoreReleaseLoadAcquire[1204] tests."

This reverts commit e08ce93.

Reason for revert: broken bot

Original change's description:
> [vm] Fix clobbered THR/R14 in StoreReleaseLoadAcquire[1204] tests.
>
> TEST=ci
> Change-Id: I8297d630b47c422b420d3d3bc8d2a6876d446eaf
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397421
> Commit-Queue: Ryan Macnak <[email protected]>
> Reviewed-by: Alexander Aprelev <[email protected]>

Change-Id: Ib7ffbc3fb6ac59918636d75e302f0a09095e5b2d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397402
Commit-Queue: Ryan Macnak <[email protected]>
Reviewed-by: Ryan Macnak <[email protected]>

Author: aam

runtime/vm/compiler/assembler/assembler_x64_test.cc

@@ -6229,10 +6229,12 @@ IMMEDIATE_TEST(AddrImmRAXByte,
                __ popq(RAX))
 
 ASSEMBLER_TEST_GENERATE(StoreReleaseLoadAcquire, assembler) {
-  // On TSAN builds StoreRelease/LoadAcquire will do a runtime
-  // call to tell TSAN about our action.
-  __ pushq(THR);
-  __ MoveRegister(THR, CallingConventions::kArg2Reg);
+  if (FLAG_target_thread_sanitizer) {
+    // On TSAN builds StoreRelease/LoadAcquire will do a runtime
+    // call to tell TSAN about our action.
+    __ MoveRegister(THR, CallingConventions::kArg2Reg);
+  }
+
   __ pushq(RCX);
   __ xorq(RCX, RCX);
   __ pushq(RCX);
@@ -6297,7 +6299,6 @@ ASSEMBLER_TEST_GENERATE(StoreReleaseLoadAcquire, assembler) {
   __ LoadAcquireFromOffset(CallingConventions::kReturnReg, RSP, 0);
   __ popq(RCX);
   __ popq(RCX);
-  __ popq(THR);
   __ ret();
 }
 
@@ -6307,10 +6308,12 @@ ASSEMBLER_TEST_RUN(StoreReleaseLoadAcquire, test) {
 }
 
 ASSEMBLER_TEST_GENERATE(StoreReleaseLoadAcquire1024, assembler) {
-  // On TSAN builds StoreRelease/LoadAcquire will do a runtime
-  // call to tell TSAN about our action.
-  __ pushq(THR);
-  __ MoveRegister(THR, CallingConventions::kArg2Reg);
+  if (FLAG_target_thread_sanitizer) {
+    // On TSAN builds StoreRelease/LoadAcquire will do a runtime
+    // call to tell TSAN about our action.
+    __ MoveRegister(THR, CallingConventions::kArg2Reg);
+  }
+
   __ pushq(RCX);
   __ xorq(RCX, RCX);
   __ pushq(RCX);
@@ -6320,7 +6323,6 @@ ASSEMBLER_TEST_GENERATE(StoreReleaseLoadAcquire1024, assembler) {
   __ addq(RSP, Immediate(1024));
   __ popq(RCX);
   __ popq(RCX);
-  __ popq(THR);
   __ ret();
 }