RFR: Remove leftover C1 workaround to fix c_rarg1 smashing

[Roman Kennke]

Apparently we worked around the c_rarg1 smashing problem before. This
can be removed now.

Testing: tier3_gc_shenandoah

OK?

# HG changeset patch
# User rkennke
# Date 1530606192 -7200
#      Tue Jul 03 10:23:12 2018 +0200
# Node ID 10d6da4616fe5aabc0ce88ae79fc6345cfb2fbae
# Parent  fad3ed60947ac28a237cc8c5505f53db91c37ff0
Remove leftover C1 workaround to fix c_rarg1 smashing

diff --git
a/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
b/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
---
a/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
+++
b/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
@@ -706,12 +706,7 @@

   // Apply storeval barrier to newval.
   if (encode) {
-    if (newval == c_rarg1 && ShenandoahStoreValEnqueueBarrier) {
-      __ mov(tmp2, newval);
-      storeval_barrier(masm, tmp2, tmp1);
-    } else {
-      storeval_barrier(masm, newval, tmp1);
-    }
+    storeval_barrier(masm, newval, tmp1);
   }

   if (UseCompressedOops) {