[dump] Remove NDEBUG from test to enable dump methods [NFC]

Summary:
Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with
LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP.

Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods.

Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so
it'll be picked up by public headers.

Differential Revision: https://reviews.llvm.org/D38406

llvm-svn: 315590
diff --git a/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp b/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
index f8d0acb..cc8511d 100644
--- a/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNRegPressure.cpp
@@ -31,7 +31,7 @@
 
 #define DEBUG_TYPE "machine-scheduler"
 
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+#ifdef LLVM_ENABLE_DUMP
 LLVM_DUMP_METHOD
 void llvm::printLivesAt(SlotIndex SI,
                         const LiveIntervals &LIS,
@@ -175,7 +175,7 @@
                          (getVGPRNum() < O.getVGPRNum());
 }
 
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+#ifdef LLVM_ENABLE_DUMP
 LLVM_DUMP_METHOD
 void GCNRegPressure::print(raw_ostream &OS, const SISubtarget *ST) const {
   OS << "VGPRs: " << getVGPRNum();
@@ -433,7 +433,7 @@
   return advance(End);
 }
 
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+#ifdef LLVM_ENABLE_DUMP
 LLVM_DUMP_METHOD
 static void reportMismatch(const GCNRPTracker::LiveRegSet &LISLR,
                            const GCNRPTracker::LiveRegSet &TrackedLR,