RFR: JDK-8200658 Fix incremental builds of hotspot on solaris

[Magnus Ihse Bursie]

On solaris, jvmciCompilerToVMInit.cpp is always recompiling when 
building incrementally.

The reason is a combination of broken code in NativeCompilation.gmk and 
special options that trigger this on solaris. (OPTIMIZATION := NONE, 
which caused OPT_C[XX]FLAGS to be empty)

Bug: https://bugs.openjdk.java.net/browse/JDK-8200658
Patch inline:
diff --git a/make/common/NativeCompilation.gmk 
b/make/common/NativeCompilation.gmk
--- a/make/common/NativeCompilation.gmk
+++ b/make/common/NativeCompilation.gmk
@@ -292,8 +292,7 @@
      endif

      ifneq ($$(strip $$($1_CFLAGS) $$($1_CXXFLAGS) $$($1_OPTIMIZATION)), )
-      $1_VARDEPS := $$($1_CFLAGS) $$($1_CXXFLAGS) $$($1_OPT_CFLAGS) \
-          $$($1_OPT_CXXFLAGS)
+      $1_VARDEPS := $$($1_CFLAGS) $$($1_CXXFLAGS) $$($1_OPTIMIZATION)
        $1_VARDEPS_FILE := $$(call DependOnVariable, $1_VARDEPS, 
$$($1_OBJ).vardeps)
      endif

/Magnus