Remove the rest of showcommands, dist goal

showcommands is all handled in soong_ui, make/kati/ninja never see the
argument.

Remove the dist goal, since we'll never pass it to ninja, only to Kati
as a modifier.

Remove DUMP_%, since that's not used anywhere (it appears to be in our
code search via the NDK build system)

Test: m -j showcommands dist
Change-Id: I0d1498128caece685e98c2c2b5b0c3f545da0e11
diff --git a/core/main.mk b/core/main.mk
index 1ca2b0a..62a9c5f 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -91,7 +91,7 @@
 # These are the modifier targets that don't do anything themselves, but
 # change the behavior of the build.
 # (must be defined before including definitions.make)
-INTERNAL_MODIFIER_TARGETS := showcommands all
+INTERNAL_MODIFIER_TARGETS := all
 
 # EMMA_INSTRUMENT_STATIC merges the static emma library to each emma-enabled module.
 ifeq (true,$(EMMA_INSTRUMENT_STATIC))
@@ -326,7 +326,7 @@
 endif
 
 
-# If they only used the modifier goals (showcommands, etc), we'll actually
+# If they only used the modifier goals (all, etc), we'll actually
 # build the default target.
 ifeq ($(filter-out $(INTERNAL_MODIFIER_TARGETS),$(MAKECMDGOALS)),)
 .PHONY: $(INTERNAL_MODIFIER_TARGETS)
@@ -1127,10 +1127,6 @@
 	@echo "$(call module-names-for-tag-list,$(ALL_MODULE_TAGS))" | \
 	      tr -s ' ' '\n' | sort -u | $(COLUMN)
 
-.PHONY: showcommands
-showcommands:
-	@echo >/dev/null
-
 .PHONY: nothing
 nothing:
 	@echo Successfully read the makefiles.