[ELF] - Recommit "[ELF] - Do not forget to fill last bytes of PT_LOADs with trap instructions."

With fix: explicitly specify ouput format for hexdump tool call.

Original commit message:

[ELF] - Do not forget to fill last bytes of PT_LOADs with trap instructions.

Previously last 4 bytes of executable loads
were not filled with trap instructions,
patch fixes this bug.

Differential revision: https://reviews.llvm.org/D36262

llvm-svn: 311315
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 2bbf654..e12de22 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -1856,7 +1856,7 @@
 }
 
 static void fillTrap(uint8_t *I, uint8_t *End) {
-  for (; I + 4 < End; I += 4)
+  for (; I + 4 <= End; I += 4)
     memcpy(I, &Target->TrapInstr, 4);
 }