X87: We should never allocate a 0-sized buffer, so never grow from 0.

port r22947

original commit message:

   We should never allocate a 0-sized buffer, so never grow from 0.

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/444403002

Patch from Chunyang Dai <chunyang.dai@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22958 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x87/assembler-x87.cc

@@ -1880,11 +1880,8 @@ void Assembler::GrowBuffer() {
 
   // Compute new buffer size.
   CodeDesc desc;  // the new buffer
-  if (buffer_size_ < 4*KB) {
-    desc.buffer_size = 4*KB;
-  } else {
-    desc.buffer_size = 2*buffer_size_;
-  }
+  desc.buffer_size = 2 * buffer_size_;
+
   // Some internal data structures overflow for very large buffers,
   // they must ensure that kMaximalBufferSize is not too large.
   if ((desc.buffer_size > kMaximalBufferSize) ||