Omit textual emitConstPool in MINIMAL build.

Noticed the "Note: Still used by emit IAS" and decided
to check if we can omit it. Saves about 3KB.

There's also the "Note: Still used by emit IAS" CFG
text header, but I haven't looked at that.

This would silently cripple the -filetype=asm or
-filetype=iasm in the MINIMAL build, but that isn't
supposed to be supported. Had to conditionalize some more
of the tests.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4080
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/952993006
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 4237e16..0576add 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -4723,7 +4723,8 @@
 
 template <typename T>
 void TargetDataX8632::emitConstantPool(GlobalContext *Ctx) {
-  // Note: Still used by emit IAS.
+  if (!ALLOW_DUMP)
+    return;
   Ostream &Str = Ctx->getStrEmit();
   Type Ty = T::Ty;
   SizeT Align = typeAlignInBytes(Ty);