Have doclava emit meaningful stack traces.

This flag enables stack traces when invoking doclava, which were
otherwise being truncated to simply be the exception name, which was
useless for debugging things.

Test: make -j32 online-system-api-sdk-docs
Bug: 38164929
Change-Id: Ie281e2b2ed988bb6d587af33256fcdee1450fc79
diff --git a/core/droiddoc.mk b/core/droiddoc.mk
index a70ab03..2285b2c 100644
--- a/core/droiddoc.mk
+++ b/core/droiddoc.mk
@@ -177,6 +177,7 @@
                 -encoding UTF-8 \
                 \@$(PRIVATE_SRC_LIST_FILE) \
                 -J-Xmx1600m \
+                -J-XX:-OmitStackTraceInFastThrow \
                 -XDignore.symbol.file \
                 $(PRIVATE_PROFILING_OPTIONS) \
                 -quiet \