Increase the maximum heap size

Sparta's message store size increases every time new messages are
inserted, regardless of how many messages are fetched.  Since we're now
inserting every round, the message store size grows considerably and we
need more heap space (since the message store is all in RAM, and indeed
in EPC, or else you'll get a major performance hit).

sparta/Cargo.toml

@@ -12,7 +12,7 @@ rayon = "1.10.0"
 
 [package.metadata.fortanix-sgx]
 stack-size=0x400000
-heap-size=0x100000000
+heap-size=0x200000000
 threads=81
 
 [profile.release]

sparta/makefile

@@ -6,7 +6,7 @@ BINARY = $(BUILD_DIR)/$(NAME)
 TARGET = $(BUILD_DIR)/$(NAME).sgxs
 SIGNATURE = $(BUILD_DIR)/$(NAME).sig
 
-HEAP_SIZE = 0x100000000
+HEAP_SIZE = 0x200000000
 STACK_SIZE = 0x400000
 MAX_THREADS = 81