[heap] Remove max executable size configuration.

src/ppc/assembler-ppc.h

Index: src/ppc/assembler-ppc.h
diff --git a/src/ppc/assembler-ppc.h b/src/ppc/assembler-ppc.h
index 04678e33938fbbb7493617edee0088d324249889..5eebdbbd17b30ae4b915f4eeed436193ebc3d5e5 100644
--- a/src/ppc/assembler-ppc.h
+++ b/src/ppc/assembler-ppc.h
@@ -1438,6 +1438,9 @@ class Assembler : public AssemblerBase {
   RelocInfoWriter reloc_info_writer;
 
  private:
+  // Avoid overflows for displacements etc.
+  static const int kMaximalBufferSize = 512 * MB;
+
   // Repeated checking whether the trampoline pool should be emitted is rather
   // expensive. By default we only check again once a number of instructions
   // has been generated.